Quantum Science & Engineering Center

Tag: Publication

QSEC faculty collaborates with NIST, ANL and ORNL to discover a new topological magnetic state

 

QSEC member, Professor Nirmal Ghimire of GMU leads a group of materials science experts from Mason, NIST, ANL, and ORNL to discover a quantum phenomenon that has the potential to become a building block of future electronic technology emerges at high temperatures from a mechanism not before realized, the result of which is published on Science Advances, doi:10.1126/sciadv.abe2680.

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Featured publication: Density functional theory-based electric field gradient database

 

QSEC members Dr. Igor Mazin, Dr. Karen Sauer and student Jaafar Ansari have recently published their collaborative work of DFT-based EFG calculation, Density functional theory-based electric field gradient database, doi:10.1038/s41597-020-00707-8, on Scientific Data.

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New publication on Valleytronics

Schematic of optical excitation and detection of valley polarization in a transition metal dichalcogenide alloy.

Fairfax, VA, 2/1/2020.

QMC member Dr. Patrick Vora and student Sean Oliver have recently published their work of Valleytronics in 2D Phase Change Materials, Valley phenomena in the candidate phase change material WSe2(1-x)Te2x, doi:10.1038/s42005-019-0277-7, on Communications Physics.

Valleytronics and neuromorphic computing are under heavy investigation as next-generation information processing technologies. In valleytronics information is stored and manipulated by moving carriers between energy band extrema (i.e., valleys) in momentum-space. Achieving this requires a material where carriers can be selectively populated in individual valleys and manipulated on demand.  In this work, the team explored the possibility of achieving a single material, e.g. 2D transition metal dichalcogenide alloys, where both valleytronic and neuromorphic functionality can be combined. Their result shows that both valley polarization and valley coherence remain large in their alloy, which also appear to host valley-polarized excitons that are more resistant to phonon-induced depolarization mechanisms. This implies that at elevated temperatures alloys may outperform pure WSe2 in valleytronic applications.

According to Dr. Vora, these results are the first systematic examination of valley properties in 2D phase change materials and point to a new class of devices where valleytronics can be utilized in concert with phase change elements in hybrid next-generation computing architectures.

For more information please see the recent publication in Communications Physics or visit the Vora Lab.