High temperature and tunable quantum anomalous Hall effect via defect-engineered topological heterostructures
Abstract
The goal of this proposal is to realize high temperature quantum anomalous Hall effect (QAHE) with tunable Chern indices via a unique combination of state-of-the-art thin film synthesis and cutting-edge scanning probe microscopy characterization. QAHE is of great fundamental interest and potential application because of dissipationless conduction without the need for an external magnetic field. If realized, this effect will allow building the lossless ÒhighwayÓ as interconnects between active devices in modern electronics. The quest for QAHE in the past decades also led to the concepts of topological classification of materials, advanced fundamental understanding of material properties with novel functionalities. QAHE was eventually demonstrated in magnetic topological insulator thin films in 2013. However, the phenomenon is only observed in handful of materials such as Cr- and V-doped (Bi,Sb)2Te3 thin films, and the full quantization is limited to sub-Kelvin temperatures, which hinders further exploration and applications of this fascinating phenomenon. There is growing evidence that magnetic and charge disorders due to doping randomness are the main culprit for this extremely low operation temperature. Therefore, finding a solution to address this disorder problem will be the key to achieving high temperature QAHE. Here, combining innovative synthesis and unique probing capabilities, the PIs will tackle this grand challenge of implementing the tunable, high temperature QAH platform by: 1) approaching ultra-clean Sb2Te3 thin films; 2) realizing low-disordered, high-Tc ferromagnetism that is compatible with the clean Sb2Te3 thin films; 3) synthesizing heterostructures and superlattices with higher and tunable Chern indices. In addition, the PIsÕ will explore the possibility of forming a completely new family of QAHE system in thin film chalcogenides with strong spin-orbit-coupling and ferromagnetism
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010108
Entities
People
- Seongshik Oh
Organizations
- Army Contracting Command
- Rutgers University
- United States Army