Events

Current events involving NTNU physicists, either ongoing or coming up in the near future or just happened at Department of Physics.

Designer droplets with «pupils»

July 9, 2013
Norwegian researchers have discovered a surprisingly simple way to control surface properties and create emulsions with droplets using electricity - and nothing else. Their findings could have implications for everything from food preparation to oil and gas production.

Designer droplets with «pupils»

July 9, 2013
Norwegian researchers have discovered a surprisingly simple way to control surface properties and create emulsions with droplets using electricity - and nothing else. Their findings could have implications for everything from food preparation to oil and gas production.

The article Active structuring of colloidal armour on liquid drops is published in Nature Communications. These authors contributed equally to this work: Paul Dommersnes, Zbigniew Rozynek and Jon Otto Fossum (Author information).

At Department of Physics (NTNU) the research is done at Laboratory for soft and complex matter studies.

Designer droplets open new possibilities

By designing droplets using electricity, researchers have opened new possibilities in physics. This technique could possibly be used for everything from extracting oil from wells to creating makeup and food.
More on Designer droplets open new possibilities

Designer dråper med pupiller (Gemini, 26. juli 2013)


Thu, 12 Sep 2013 11:35:51 +0200

Inauguration of the new NORTEM JEOL microscopes in Trondheim

August 13, 2013
The event will take place on Tuesday 10. September 2013 in auditorium R8, Realfagbygget at NTNU. We hope potential users from the materials and the microscopy research fields from Trondheim, the Nordic countries and the rest of the world will come and join us in the celebration of our new microscopes.

Norwegian Centre for Transmission Electron Microscopy (NORTEM)

Inauguration of the new NORTEM JEOL microscopes in Trondheim

- September 10. 2013

August 13, 2013
The event will take place on Tuesday 10. September 2013 in auditorium R8, Realfagbygget at NTNU. We hope potential users from the materials and the microscopy research fields from Trondheim, the Nordic countries and the rest of the world will come and join us in the celebration of our new microscopes.


Research on teaching resources and learning environments in science education

June 19, 2013
Photo: Allyson MacdonaldNordic workshop: Research on teaching resources and learning environments in science education in the Nordic countries, 8th -10th October 2013 in Reykjavík, University of Iceland. The aim of the workshop is bring together researchers and PhD students in science education to discuss research approaches and results, and share ideas for new research projects.

Research on teaching resources and learning environments in science education

June 19, 2013
Photo: Allyson MacdonaldNordic workshop: Research on teaching resources and learning environments in science education in the Nordic countries, 8th -10th October 2013 in Reykjavík, University of Iceland. The aim of the workshop is bring together researchers and PhD students in science education to discuss research approaches and results, and share ideas for new research projects.

The focus in the workshop will on the development and use of teaching and learning resources in science education and the design of learning environments. The workshop is the final event in the NorSEd network, and will be a source of inspiration and ideas for bringing research and development in these areas of science education further in a Nordic setting. NorSEd provides financial support for travel and accommodation for participants.

More on the workshop on Research on teaching resources and learning environments in science education


New book on superconductivity by Kristian Fossheim

Kristian Fossheim, President of The Royal Norwegian Society of Sciences and Letters (DKNVS) and Professor emeritus at Department of Physics (NTNU).May 15, 2013
Kristian Fossheim has written a book about discoveries and discoverers in the field of superconductivity, Superconductivity: Discoveries and Discoverers. Ten physics Nobel laureates tell their story. Fossheim is Professor emeritus at Department of Physics (NTNU) and President of The Royal Norwegian Society of Sciences and Letters (DKNVS).

New book on superconductivity by Kristian Fossheim

Kristian Fossheim, President of The Royal Norwegian Society of Sciences and Letters (DKNVS) and Professor emeritus at Department of Physics (NTNU).May 15, 2013
Kristian Fossheim has written a book about discoveries and discoverers in the field of superconductivity, Superconductivity: Discoveries and Discoverers. Ten physics Nobel laureates tell their story. Fossheim is Professor emeritus at Department of Physics (NTNU) and President of The Royal Norwegian Society of Sciences and Letters (DKNVS).

Publisher's description

This book is about the work of 10 great scientists; who they were and are, their personal background and how they achieved their outstanding results and took their prominent place in science history. We follow one of physics and science history's most enigmatic phenomena, superconductivity, through 100 years, from its discovery in 1911 to the present, not as a history book in the usual sense, but through close ups of the leading characters and their role in that story, the Nobel laureates, who were still among us in the years 2001-2004 when the main round of interviews was carried out. Since then two of them already passed away.

Abstract

Physics is a science which aims at answering the big mysteries in Nature. Physicists have always been attracted by the greatest challenges. But sometimes even the most demanding problems reveal themselves little by little. On the 8th of April 1911 a discovery was made through an apparently simple experiment in a glass flask of very special design in a physics laboratory in Leiden, Holland. The experiment set in motion a series of events with few parallels in the history of science. But physics was far from ready for the advent of superconductivity, the enigmatic phenomenon which Heike Kamerlingh Onnes and his student Gilles Holst had just observed. Today, more than a hundred years later, after great scientific research efforts and big investments, and after many impressive scientific and technical breakthroughs, a cloud of mystery still hovers over aspects of superconductivity. Nature continues to play her elusive game with the best minds of physics.

The book and the author


Mon, 19 Aug 2013 12:14:43 +0200

Workshop on Water Phenomena in PEM

April 30, 2013
PEM 2013. Trondheim piersThe workshop Water Phenomena in PEM: Sorption, Swelling and Breakthrough Processes, will be held in Trondheim from 3rd to 4th October 2013. It will focus on recent advances in the fundamental understanding of polymer electrolyte membranes (PEM), both from an experimental and a theoretical point of view.
More on the workshop PEM 2013

Workshop on Water Phenomena in PEM

- October 3 - 4. 2013

April 30, 2013
PEM 2013. Trondheim piersThe workshop Water Phenomena in PEM: Sorption, Swelling and Breakthrough Processes, will be held in Trondheim from 3rd to 4th October 2013. It will focus on recent advances in the fundamental understanding of polymer electrolyte membranes (PEM), both from an experimental and a theoretical point of view.
More on the workshop PEM 2013

Contact: Peter Berg


Alex Hansen, editor of open access journal of Physics

April 15, 2013Alex Hansen
Alex Hansen, professor at Department of Physics, has been appointed Speciality Chief Editor of the Interdisciplinary Physics Section of the open access journal "Frontiers in Physics" which will be launched this year. The Frontiers series of journals was started in 2007 and has become the leading journal in disciplines such as neurophysiology. 

Alex Hansen, editor of open access journal of Physics

April 15, 2013Alex Hansen
Alex Hansen, professor at Department of Physics, has been appointed Speciality Chief Editor of the Interdisciplinary Physics Section of the open access journal "Frontiers in Physics" which will be launched this year. The Frontiers series of journals was started in 2007 and has become the leading journal in disciplines such as neurophysiology. 

Frontiers is an online platform for the scientific community to publish open-access articles and network with colleagues. The Frontiers Research Network is a rapidly growing research network for all academic communities. It includes the world's leading scientists, academics, clinicians, researchers and more. Alex Hansen (presentation in Frontier).

 


Anne Borg becomes new dean at NT

Anne BorgMarch 20, 2013
Anne Borg is the new dean at the Faculty of Natural Sciences and Technology. Anne Borg is professor in physics and has been vice dean for education at the faculty for the last eight years. The new dean will begin the position 1. August 2013.

Anne Borg becomes new dean at NT

Anne BorgMarch 20, 2013
Anne Borg is the new dean at the Faculty of Natural Sciences and Technology. Anne Borg is professor in physics and has been vice dean for education at the faculty for the last eight years. The new dean will begin the position 1. August 2013.

Department of Physics want to congratulate a dear colleague, Anne, with the new and interesting job.

More on NTNUs new deans and VM director


Sunspots and solar rotation

Winter sunDesember 20, 2012
Here you can read a short article on sunspots and solar rotation.  You can study it for yourself during the Christmas holiday. We celebrate the solstice folks! Merry Christmas.

Sunspots and solar rotation

Winter sunDesember 20, 2012
Here you can read a short article on sunspots and solar rotation.  You can study it for yourself during the Christmas holiday. We celebrate the solstice folks! Merry Christmas.

Physics Education. Volume 48. Number 1, January 2013The article is written by Jonas R. Persson. Physics Education. Volume 48 Number 1, January 2013.

Sunspots and solar rotation

With the transit of Venus 2012 and a growing number of sunspots, there is increased interest in observing the Sun. Going beyond observing, it is possible to determine the rotation of the Sun using your own or preferably better observations available on the internet.
More on Sunspots and solar rotation

Jonas R. Persson, Associate Professor at Department of Physics, NTNU.


Mon, 19 Aug 2013 12:16:35 +0200

PhD Candidate Amna Noreen got the Certificate of Merit

Amna Noreen. Photo: Asif MushtaqSeptember 20, 2012
The PhD Candidate Amna Noreen at the Section for Theoretical Physics, Department of Physics, was awarded the Certificate of Merit for her presentation at the 2012 International Conference of Computer Science and Engineering. She was one of two awarded students.

PhD Candidate Amna Noreen got the Certificate of Merit

Amna Noreen. Photo: Asif MushtaqSeptember 20, 2012
The PhD Candidate Amna Noreen at the Section for Theoretical Physics, Department of Physics, was awarded the Certificate of Merit for her presentation at the 2012 International Conference of Computer Science and Engineering. She was one of two awarded students.

The International Association of Engineers organizes the Best Paper Award and Best Student Paper Award for each WCECS conference. The candidate papers are judged on originality, significance, correctness, and clarity.

Certificate of merit (student) for The 2012 International Conference of Computer Science and Engineering

Amna Noreen
Title: Estimating Coefficients of Frobenius Series by Legendre Transform and WKB Approximation [pdf]

Abstract:

The Frobenius method can be used to represent solutions of ordinary differential equations by (generalized) power series. It is useful to have prior knowledge of the coefficients of this series. In this contribution we demonstrate that the magnitude of the coefficients can be predicted to surprisingly high accuracy by a Legendre transformation of WKB approximated solutions to the differential equations.

PhD Candidate Amna Noreen was awarded the 'Certificate of Merit' for her presentation at the 2012 International Conference of Computer Science and Engineering. Photo: Asif Mushtaq.


Mon, 19 Aug 2013 12:16:53 +0200

Guest lecture on Surface X-ray Diffraction Studies (SXRD)

November 30, 2012
Robert Felici, group leader of the Structure of Materials Group at ESRF will give a guest lecture at Department of Physics Wednesday December 5th at 10:15 in Realfagbygget D4-132. "Surface X-ray Diffraction Studies at the ID03 Beamline of the ESRF".
 

Guest lecture on Surface X-ray Diffraction Studies (SXRD)

- December 5. at 10:15

November 30, 2012
Robert Felici, group leader of the Structure of Materials Group at ESRF will give a guest lecture at Department of Physics Wednesday December 5th at 10:15 in Realfagbygget D4-132. "Surface X-ray Diffraction Studies at the ID03 Beamline of the ESRF".
 

R. Felici, European Synchrotron Radiation Facility, Grenoble, France.

Surface X-ray Diffraction Studies at the ID03 Beamline of the ESRF

X-rays are an ideal probe for studying structural properties of matter and, thanks to
the brilliance of synchrotron sources, they are also employed to determine the atomic structure and morphology of surfaces and interfaces.

Aim of this talk is to provide the basic knowledge on the main techniques used in this field i.e. x-ray reflection, surface x-ray diffraction and grazing incidence small angle scattering together with a description of the beamline layout and equipment.

Examples will be shown dealing with the adsorption of organic molecules on noble metals surfaces /1,2/ and with the in-situ characterization of the structure and morphology of a catalyst surface during the heterogenous catalytic oxidation of CO /3,4/.

References

  1. R. Felici et al, Nat. Mat. 4 (2005) 688
  2. M. Hinterstein et al., Phys. Rev. B77 (2008) 153412
  3. R. van Rijn et al., Phys. Chem. Chem. Phys. 13 (2011) 13167
  4. B.L. Hendriksen et al., Nat. Chem. 2 (2010) 730  

Mon, 19 Aug 2013 12:17:14 +0200

About clay properties in Nature's Scientific Reports

Elisabeth Lindbo HansenSeptember 17, 2012
Department of Physics research group, Laboratory for soft and complex matter studies, has recently published an article in the journal Scientific Reports, Nature's new open journal. The research group Laboratory for soft and complex matter studies are studying soft and complex materials and has now published the article "Swelling transition of a clay induced by heating".

About clay properties in Nature's Scientific Reports

Elisabeth Lindbo HansenSeptember 17, 2012
Department of Physics research group, Laboratory for soft and complex matter studies, has recently published an article in the journal Scientific Reports, Nature's new open journal. The research group Laboratory for soft and complex matter studies are studying soft and complex materials and has now published the article "Swelling transition of a clay induced by heating".

The research group's projects

More on the publication

Swelling transition of a clay induced by heating

Clays are naturally occurring mineral nanoparticles that are found in soils and sediments around the world. As an abundant and cheap natural resource, clays have had numerous uses historically; examples include the use of clays in pottery, in traditional medicine, and in the construction of housing. Today, clays are also important in a modern context: they are used in oil recovery, as rheology modifiers in cosmetics, paints and drilling fluids, and as essential ingredients in nanocomposites.

Generically, clays can be divided into two broad subclasses. 'Active' clays are clays which swell macroscopically when they are put into contact with water. These clays are known to form stable gels at very low volume fractions. 'Passive' clays on the other hand have a limited water uptake, leading to very different mechanical properties.

It has been unclear so far what mechanisms underlie clay swelling. In our study, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. Our experiments were made possible because we studied a synthetic clay whose attraction energy was in the range where a temperature increase from 25 to 75 oC would cause swelling to occur.

Based on our observations, we propose a simple model for the swelling transition. While net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other as stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling.

Elisabeth Lindbo Hansen, Henrik Hemmen, Davi de Miranda Fonseca, C. Coutant, Kenneth D. Knudsen, Tomás PlivelicDaniel Bonn, Jon Otto Fossum

Paper was published in Scientific Reports 2, 618 (2012) on nature.com.


Mon, 19 Aug 2013 12:18:01 +0200

Workshop on Soft matter Physics and Biomembranes

May 16, 2013International Workshop; Soft Matter Physics And Biomembranes
The international workshop on Soft Matter Physics And Biomembranes will take place at University of Iceland in Reykjavik, May 21-24, 2013.

Workshop on Soft matter Physics and Biomembranes

- Iceland, May 21-24. 2013

May 16, 2013International Workshop; Soft Matter Physics And Biomembranes
The international workshop on Soft Matter Physics And Biomembranes will take place at University of Iceland in Reykjavik, May 21-24, 2013.

The event is organized by the Nordic Network in Soft Matter Physics (NordSoft) and the Nordic Network for Dynamic Biomembrane Research (DBR).

Organizers: Jon Otto Fossum (NTNU) and Aldo Jesorka (Chalmers)

More on the workshop

Invited speakers, Schedule and Talks;

International Workshop; Soft Matter Physics And Biomembranes [pdf]


Mon, 19 Aug 2013 12:14:03 +0200

Most read articles in ACS Applied Materials & Interfaces 2012

September 13, 2012
Professor Mikael Lindgren is coauthor of the publication that is one of the most read articles in ACS Applied Materials & Interfaces the second quarter of 2012. This is a great recognition of Michael's contribution during his stay University of Lyon and Ens de Lyon.

Most read articles in ACS Applied Materials & Interfaces 2012

September 13, 2012
Professor Mikael Lindgren is coauthor of the publication that is one of the most read articles in ACS Applied Materials & Interfaces the second quarter of 2012. This is a great recognition of Michael's contribution during his stay University of Lyon and Ens de Lyon.


Physics Friday Colloquia has started

Realfagbygget i høstsol. Photo: Irene AspliAugust 31, 2012
Department of Physics organizes a series of Physics colloquia. The seminars will be held every Friday. 2:15 p.m. to 3:00 p.m. in the auditorium R5 in Realfagbygget, NTNU. The Physics Friday Colloquium is open to everybody. Coffee, tea and biscuits from at. 14:00.
More on Physics Friday Colloquia ...

Physics Friday Colloquia has started

Realfagbygget i høstsol. Photo: Irene AspliAugust 31, 2012
Department of Physics organizes a series of Physics colloquia. The seminars will be held every Friday. 2:15 p.m. to 3:00 p.m. in the auditorium R5 in Realfagbygget, NTNU. The Physics Friday Colloquium is open to everybody. Coffee, tea and biscuits from at. 14:00.
More on Physics Friday Colloquia ...

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Mon, 19 Aug 2013 12:20:08 +0200

Workshop on Water Phenomena in PEM

September 12. 2013
In early October the workshop Water Phenomena in PEM: Sorption, Swelling and Breakthrough Processes will stay in Trondheim.

Workshop on Water Phenomena in PEM

- October 3rd to 4th 2013 in Trondheim

September 12. 2013
In early October the workshop Water Phenomena in PEM: Sorption, Swelling and Breakthrough Processes will stay in Trondheim.


The new NORTEM TEMs in Trondheim

Professor Randi Holmestad on the inauguration of the new NORTEM JEOL microscopes in Trondheim, September 10. 2013 . Photo: Irene Aspli September 16. 2013
Last Tuesday the new microscopes (TEM) at NTNU and SINTEF inaugurated and the event took place in Realfagbygget NTNU. Project Manager Spyros Diplas (SINTEF) welcomed. Then Randi Holmestad (NTNU) told the history of TEM in Trondheim.

The new NORTEM TEMs in Trondheim

- Inauguration of the new NORTEM JEOL microscopes

Professor Randi Holmestad on the inauguration of the new NORTEM JEOL microscopes in Trondheim, September 10. 2013 . Photo: Irene Aspli September 16. 2013
Last Tuesday the new microscopes (TEM) at NTNU and SINTEF inaugurated and the event took place in Realfagbygget NTNU. Project Manager Spyros Diplas (SINTEF) welcomed. Then Randi Holmestad (NTNU) told the history of TEM in Trondheim.

History of TEM in Trondheim

John Walmsley shows off the flagship instrument, a JEOL JEM-ARM200F ColdFEG electron source with probe and image correction. Photo: Irene AspliThe TEM history started by Professor Ragnvald Høier in 1972 and continued until the first Jeol2010F was installed at Department of Physics in 2001. Randi Holmestad told about the long road to the award. The TEM group started with the application for funding already in 2006. In 2009, the Norwegian Centre for Transmission Electron Microscopy (NORTEM) was established. After several suggestions and applications were NORTEM large-scale infrastructure projects granted 58 MNOK from The Research Council of Norway. The job of implementation, negotiations and contracts could start.

Laboratories and transmission electron microscopes (TEM) was built during the past year. In October 2013, the three new microscopes will come into use. The three new microscopes are JEM-ARM200F (JEOL double corrected), JEM-2100F TEM and JEM-2100 LaB6 TEM.

NORTEM today

TEM Gemini Centre consists of a team of six SINTEF researchers, four NTNU researchers, three engineers, seven master's students, three postdocs and nine PhD students. The project is funded by The Research Council of Norway together with the three partners SINTEF, Norwegian University of Science and Technology (NTNU) and University of Oslo (UiO). NORTEM project is divided into two nodes, in Trondheim and Oslo, distribution 50-50 percent.

JEOL Centre contract was signed by SINTEF's President Unni Steinsmo, President JEOL Ltd. Gon'emon Kurihara and NTNUs Pro-Rector for Research Kari Melby. Guests and participants were given a guided tour in the the laboratories and the new microscopes. After the official opening it was held a technical seminar with seven invited speakers from around the world, giving presentations about what is possible to achieve with the new generation of TEM. The seminar had more than 50 participants.

From the left; John Walmsley, Unni Steinsmo, Rudie Spooren, Kari Melby, Spyros Diplas, Gon'emon Kurihara og Randi Holmestad. Photo: Irene Aspli

The JEOL delegation, including the president Gonemon Kurihara (JEOL president), Siegfried Falch (JEOL Germany) , Yuichi Matsumoto (JEOL, Head of European interface), Tsutomu Morita (JEOL Europe) Matthias Rodewald (JEOL Germany), Mats Bergius (JEOL AB), Fredrik Andersson (JEOL AB). Photo: Randi Holmestad

Invited speakers at the seminar in advanced TEM. From left Ian MacLaren (Glasgow University), Per Persson (Linköping University), Takeshi Kasama (CEN, DTU), Jian Min Zuo (University of Illinois), Masahiro Kawasaki (JEOL USA), Sarah Haigh (Manchester University) and Williams Lefebvre (University of Rouen). Photo: Randi Holmestad

More on Inauguration of the new NORTEM JEOL microscopes in Trondheim

More pictures of the Inauguration of the new NORTEM JEOL microscopes in Trondheim on the NT-faculty facebook page

Nye supermikroskop på plass ved NTNU (Norwegian)


Tue, 18 Mar 2014 11:35:59 +0100

4th NorTEMnet workshop on advanced TEM in Trondheim

NORTEM microscope. Photo: Irene Aspli/NTNUNovember 4. 2013
The 4th NorTEMnet workshop on advanced TEM is organized at NTNU in Trondheim, January 8.-10. 2014. This workshop will be focused on STEM - there will be three days of lectures, computer exercises and hands-on practical sessions using the new NORTEM infrastructure in Trondheim (JEOL 2100, 2100F and ARM200F).

4th NorTEMnet workshop on advanced TEM in Trondheim

NORTEM microscope. Photo: Irene Aspli/NTNUNovember 4. 2013
The 4th NorTEMnet workshop on advanced TEM is organized at NTNU in Trondheim, January 8.-10. 2014. This workshop will be focused on STEM - there will be three days of lectures, computer exercises and hands-on practical sessions using the new NORTEM infrastructure in Trondheim (JEOL 2100, 2100F and ARM200F).


Lars Onsager Professorship 2013 to Reinout Quispel

Onsager Medal NTNUAugust 30. 2013
Onsager Professor 2013, Reinout Quispel at La Trobe University, Melbourne, Australia. Thursday September 5. 2:15 to 3:00 p.m. the Onsager Professor will give a lecture titled «Geometric Numerical Integration of Differential Equations». The lecture will take place in the auditorium R9, Realfagbygget.

Lars Onsager Professorship 2013 to Reinout Quispel

- Lecture by the Onsager Professor

Onsager Medal NTNUAugust 30. 2013
Onsager Professor 2013, Reinout Quispel at La Trobe University, Melbourne, Australia. Thursday September 5. 2:15 to 3:00 p.m. the Onsager Professor will give a lecture titled «Geometric Numerical Integration of Differential Equations». The lecture will take place in the auditorium R9, Realfagbygget.

Professor Reinout Quispel will beOnsager Medal NTNU awarded the Onsager medal on this occasion.

Abstract

«Geometric Numerical Integration of Differential Equations»

Geometric integration is the numerical integration of a differentialequation, while preserving one or more of its geometric/physical properties exactly, i.e. to within round-off error. Many of these geometric properties are of crucial importance in physical applications: preservation of energy, momentum, angular momentum, phase-space volume, symmetries, time-reversal symmetry, symplectic structure and dissipation are examples. The field has tantalizing connections to dynamical systems, as well as to Lie groups. This talk starts by presenting a survey of geometric numerical integration methods for differential equations. If time permits, this will be followed by a discussion of some recent developments.


Lars Onsager Lecture and Professorship

The Lars Onsager Professorship for 2013 has been awarded to Professor Reinout Quispell, La Trobe University, Melbourne, Australia. For further information contact Brynjulf Owren or Helge Holden.

More on The Lars Onsager Lecture and Professorship


Tue, 26 Nov 2013 16:06:13 +0100

Featured lab in Soft Matter World

September 19, 2012
In the September issue of Soft Matter World was J.O. Fossum's laboratory at our department selected in this month's feature article. Soft Matter World describes the latest research in the clay-based materials and studies of soft and complex materials at the Laboratory for soft and complex matter studies.

Featured lab in Soft Matter World

September 19, 2012
In the September issue of Soft Matter World was J.O. Fossum's laboratory at our department selected in this month's feature article. Soft Matter World describes the latest research in the clay-based materials and studies of soft and complex materials at the Laboratory for soft and complex matter studies.


Thu, 07 Nov 2013 14:49:46 +0100

Justin Wells has published in Nano Letters

Nano Letters, March 12, 2014, Volume 14, Issue 3March 17. 2014
Justin has recently published in the distinguished science magazine Nano Letters. He and his partners from Denmark and Australia published an article Valley Splitting in a Silicon Quantum Device Platform.

Justin Wells has published in Nano Letters

Nano Letters, March 12, 2014, Volume 14, Issue 3March 17. 2014
Justin has recently published in the distinguished science magazine Nano Letters. He and his partners from Denmark and Australia published an article Valley Splitting in a Silicon Quantum Device Platform.

Justin WellsAssociate Professor Justin Wells is interest in atmoic-scale electronics, and the relevance for quantum computation.

Department of Physics congratulates Justin with this great recognition!

Abstract

By suppressing an undesirable surface Umklapp process, it is possible to resolve the two most occupied states (1Γ and 2Γ) in a buried two-dimensional electron gas (2DEG) in silicon. The 2DEG exists because of an atomically sharp profile of phosphorus dopants which have been formed beneath the Si(001) surface (a δ-layer). The energy separation, or valley splitting, of the two most occupied bands has critical implications for the properties of δ-layer derived devices, yet until now, has not been directly measurable. Density functional theory (DFT) allows the 2DEG band structure to be calculated, but without experimental verification the size of the valley splitting has been unclear. Using a combination of direct spectroscopic measurements and DFT we show that the measured band structure is in good qualitative agreement with calculations and reveal a valley splitting of 132 ± 5 meV. We also report the effective mass and occupation of the 2DEG states and compare the dispersions and Fermi surface with DFT.

More on the publication; Valley Splitting in a Silicon Quantum Device Platform


Twisterlike (bubble champagne). Photo: Jon Otto Fossum

Open Lectures and Seminars