Sandia Labs FY22 Laboratory Directed Research & Development Annual Report

FY22 ANNUAL REPORT

SEMICONDUCTOR TWISTRONICS WILL ENABLE FUTURE QUANTUM INFORMATION SCIENCE APPLICATIONS. The three-year semiconductor twistronics project aims to advance the field of moiré quantum

new quantum states and correlated phases. By making semiconductor MQMs a new QIS materials platform, future QIS applications can build on, and be compatible with, the sophistication and maturity of the state-of-the-art semiconductor industry. This project, conducted in collaboration with Sandia Securing Top Academic Research Talent at Historically Black Colleges and University

materials (MQM) for quantum information science (QIS) applications by exploring MQMs composed entirely of compound semiconductors. Four years after the exciting discoveries in magic-angle twisted bilayer graphene, traditional MQMs face daunting issues. These challenges are inevitable in

(a) A schematic showing two hexagonal patterns etched into the 2D electron gas of an Indium Arsenide (InAs) quantum well, twisted to form a moiré pattern. (b) Theoretical modeling showing the presence of a flat band separated from other continuous bands. (c) Preliminary observations, in a prototype semiconductor moiré structure, of unexpected quantum transport features (triangles). These features are in addition to the usual peaks (diamonds) and are reminiscent of exotic quantum states observed in twisted bilayer graphene. They are absent in InAs structures without moiré patterning.

traditional MQMs due to reliance on mechanical exfoliation of flakes to create one-off devices. The Sandia research eliminates major device-to device variations by using lithographically defined semiconductor MQMs. This further enables controlled parameter tuning over wide ranges. Such tunability is essential to unravel mysterious quantum materials phenomena that is already observed but poorly understood, and to discover

(START HBCU) partners Norfolk State University and Prairie View A&M University, Sandia Alliance partner University of Illinois at Urbana-Champaign, and the University of Southern California and University of Texas at Dallas, has resulted in a publication in Nanotechnology , three Technical Advances, and two patent applications that are in prosecution. (PI: Wei Pan)

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