Joint Seminar GRK 1782 & SFB 1083

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More than 80 participants, from master-student to principal investigator, from Marburg, Gießen, Jülich and Münster ventured to Kloster Volkenroda in Thuringia for a multi-day seminar featuring talks and posters by the programs’ young research staff.

After an International Summer School in 2014 in San Sebastian in Spain, co-organized by SFB guest project GP1 based at the Donostia International Physics Center (DIPC), it was the second time that the two DFG-funded programs came together to discuss their science projects, present the latest results and provide a networking forum for existing and new collaborations.

The meeting provided a balanced mix of more senior presentations and first-time talks or posters by new PhD-students and the current crop of MSc-students in the various projects. The meeting also provided a great forum for interaction with those program-members from outside of Marburg – seeing each other in person, standing side-by-side while discussing science, forming joint memories of the “pilgrimage to Mühlhausen”, and simply talking with each other form a solid base for future interaction by email, skype and phone.
For more details check out the program.

First papers online – JPCM Special Issue on Internal Interfaces

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JPCM’s Special Issue on Internal Interfaces is being guest-edited by SFB 1083 principal investigators Michael Gottfried (A4) and Ulrich Höfer (B5, B6). The first two papers of the special issue are now online and as the deadline for submission is still in the future we are expecting many more papers to come out soon.

The first two papers are a joint-submission by SFB-projects A6 (Tonner) with A3 (Jakob) and a submission by SFB-project B4 (SW Koch).

L. Meckbach, U. Huttner, L. Bannow, T. Stroucken, and S. W. Koch
Interlayer excitons in transition-metal dichalcogenide heterostructures with type-II band alignment
J. Phys.: Condens. Matter 30 (2018) 354002 (10pp) DOI:10.1088/1361-648X/aad984.

N. L. Zaitsev, P. Jakob, and R. Tonner
Structure and vibrational properties of the PTCDA/Ag(111) interface: bilayer versus monolayer
J. Phys.: Condens. Matter 30 (2018) 354001 (8pp) DOI:10.1088/1361-648X/aad576

Please check out our page dedicated to the JPCM Special Issue on Internal Interfaces for more details and current information.

Lightwave valleytronics in WSe2 – Publication by B4 (SW Koch) in Nature

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As part of their ongoing theory-experiment collaboration, members from project B4 (group of Prof. S.W. Koch) jointly with colleagues from Regensburg (group of Prof. Huber) and the University of Michigan (former co-PI in B4 Prof. Kira) demonstrate how to control and manipulate the quantum states of optically excited electrons in modern quasi-two dimensional semiconductor materials. In particular, they show that the valley pseudo-spin in a tungsten diselenide system can be switched at ultrafast speeds by applying an intense light field.

Energy-landscape in a WSe2-semiconductor depicted as blue hills. Electrons are accelerated from one valley to the next (yelloworange) with the colored arrows indicating change of the valley-pseudospin. (Ill.: F. Langer, Univ. Regensburg; use only in context of paper published).

In today’s information technology, quantum effects still play a mostly supporting role. This should change in the future, as research into quantum information technology paves the way towards efficient storage, processing and communication – eventually replacing “Moore’s law” with its own. The basis are robust and quickly switchable electronic states provided by the so-called “valley pseudospin” that can be changed when energized electrons are optically driven between distinct energetic valleys in the hexagonal layered materials.

This controlled ultrafast switching between the occupation of different bandstructure minima provides an important step in the new area of light driven electronics, opening the field for lightwave valleytronics. Ultimately this may become important in developing room-temperature quantum signal processing.

Publication

F. Langer, C. P. Schmid, S. Schlauderer, M. Gmitra, J. Fabian, P. Nagler, C. Schüller, T. Korn, P. G. Hawkins, J. T. Steiner, U. Huttner, S. W. Koch, M. Kira & R. Huber, Lightwave valleytronics in a monolayer of tungsten diselenide,
Nature 557 (2018) 76-80, DOI: 10.1038/s41586-018-0013-6

See also press release (
Uni Marburg in German;
UMICH Ann Arbor in English), a video (UMICH Ann Arbor) and articles
in
Oberhessische Presse and Rhein-Neckar-Zeitung.

Contact
Prof. Dr. Stephan W. Koch
Dept. of Physics, Philipps-Universität Marburg
SFB 1083 Project B4 (SW Koch)
Tel. +49 (0)6421 28-21336
Email: Stephan.W.Koch@physik.uni-marburg.de