Milli-Kelvin Microwave Impedance Microscope for Research on Nontrivial Topological Boundary States
Abstract
This DURIP project aims to implement the first dilution-refrigerator-based milli-Kelvin microwave impedance microscope (MIM) for the study of topological edge channels in quantum spin Hall and quantum anomalous Hall systems. The boundaries of these exotic quantum states can support dissipationless electrical transport and may serve as perfectly conducting channels in radio-frequency nanoelectronic and spintronic devices. While both effects have been successfully demonstrated by macroscopic transport measurements, much remains to be explored on the microscopic details of the edge states. Local probing of these states by the MIM is there not only of great academic interest but also of technological importance to realize high-speed and lowpower electronics for defense applications. By integrating the MIM technique and the dilution refrigerator with a base temperature below 100 mK, the PIÕs group will be able to quantitative measure the widths of quantum spin Hall and quantum anomalous Hall edge channels. The effects of temperature, and magnetic field, and local perturbation due to a tip bias on the edge and bulk states will also be studied. The multi-domain formation and a network of chiral edges during the magnetization reversal in the quantum anomalous Hall systems will be investigated. The proposed program introduces a novel tool to study the nanoscale electronic structure of topologically ordered quantum states at ultra-low temperatures. The work will establish a new research direction and augment existing Defense programs at UT-Austin. Graduate and undergraduate students will be recruited and trained for their participation in this project funded by the Army Research Office
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810467
Entities
People
- Keji Lai
Organizations
- Army Contracting Command
- United States Army
- University of Texas at Austin