Helium-efficient Cryogenic Microwave Impedance Microscopy for Research on Topological Quantum States
Abstract
This DURIP program aims to integrate a helium reliquefier with the milli-Kelvin microwave impedance microscope for the study of topologically ordered quantum states. The boundaries of many topological solid-state systems can support dissipationless electrical transport and may serve as perfectly conducting wires in radio-frequency nanoelectronic and spintronic devices. To date, much remains to be explored on the microscopic details of these edge channels, such as their spatial dimensions and the dependence on temperature, magnetic field, and sample disorders. Local probing of these states is thus not only of great academic interest but also of technological importance to realize high-speed and low-power electronics. The instrument will enable the continuous operation of a dilution-refrigerator-based microwave microscope with minimal helium consumption. The researchers plan to image the local conductance of topologically non-trivial phases such as quantum spin Hall state, quantum anomalous Hall state, and Axion insulator state, with a spatial resolution around 10 nm. The widths of quantum spin Hall and quantum anomalous Hall edge channels and the multi-domain structure will be investigated at temperatures as low as 50 mK. It is expected that the electrical properties of edge and bulk states at the frequency spectrum of 0.1 Ð 10 GHz will be of particular interest for defense applications. The proposed program introduces a novel tool to study the nanoscale electronic structure of topologically ordered quantum states at ultralow temperatures. The work will establish a new research direction and augment existing Defense programs at University of Texas at Austin. Graduate and undergraduate students will be recruited and trained during their participation in this project funded by the Army Research Office.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010049
Entities
People
- Keji Lai
Organizations
- Army Contracting Command
- United States Army
- University of Texas at Austin