Implementing microwave impedance microscopy in a dilution refrigerator

Zhanzhi Jiang; Su Kong Chong; Peng Zhang; Peng Deng; Shizai Chu; Shahin Jahanbani; Kang L Wang; Keji Lai

doi:10.1063/5.0138831

Implementing microwave impedance microscopy in a dilution refrigerator

Rev Sci Instrum. 2023 May 1;94(5):053701. doi: 10.1063/5.0138831.

Authors

Zhanzhi Jiang¹, Su Kong Chong², Peng Zhang², Peng Deng², Shizai Chu¹, Shahin Jahanbani¹, Kang L Wang², Keji Lai¹

Affiliations

¹ Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
² Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, USA.

PMID: 37125853
DOI: 10.1063/5.0138831

Abstract

We report the implementation of a dilution refrigerator-based scanning microwave impedance microscope with a base temperature of ∼100 mK. The vibration noise of our apparatus with tuning-fork feedback control is as low as 1 nm. Using this setup, we have demonstrated the imaging of quantum anomalous Hall states in magnetically (Cr and V) doped (Bi, Sb)2Te3 thin films grown on mica substrates. Both the conductive edge modes and topological phase transitions near the coercive fields of Cr- and V-doped layers are visualized in the field-dependent results. Our study establishes the experimental platform for investigating nanoscale quantum phenomena at ultralow temperatures.