Probing the mesoscopic size limit of quantum anomalous Hall insulators

Peng Deng; Christopher Eckberg; Peng Zhang; Gang Qiu; Eve Emmanouilidou; Gen Yin; Su Kong Chong; Lixuan Tai; Ni Ni; Kang L Wang

doi:10.1038/s41467-022-31105-w

Probing the mesoscopic size limit of quantum anomalous Hall insulators

Nat Commun. 2022 Jul 22;13(1):4246. doi: 10.1038/s41467-022-31105-w.

Authors

Peng Deng¹, Christopher Eckberg^{2

3

4}, Peng Zhang⁵, Gang Qiu⁵, Eve Emmanouilidou⁶, Gen Yin⁵, Su Kong Chong⁵, Lixuan Tai⁵, Ni Ni⁶, Kang L Wang^{7

8}

Affiliations

¹ Department of Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, CA, USA. dengpeng@g.ucla.edu.
² Fibertek Inc, Herndon, VA, USA. chris.eckberg@fibertek.com.
³ US Army Research Laboratory, Adelphi, MD, USA. chris.eckberg@fibertek.com.
⁴ US Army Research Laboratory, Playa Vista, CA, USA. chris.eckberg@fibertek.com.
⁵ Department of Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, CA, USA.
⁶ Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA.
⁷ Department of Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, CA, USA. wang@ee.ucla.edu.
⁸ Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA. wang@ee.ucla.edu.

Abstract

The inelastic scattering length (L_s) is a length scale of fundamental importance in condensed matters due to the relationship between inelastic scattering and quantum dephasing. In quantum anomalous Hall (QAH) materials, the mesoscopic length scale L_s plays an instrumental role in determining transport properties. Here we examine L_s in three regimes of the QAH system with distinct transport behaviors: the QAH, quantum critical, and insulating regimes. Although the resistance changes by five orders of magnitude when tuning between these distinct electronic phases, scaling analyses indicate a universal L_s among all regimes. Finally, mesoscopic scaled devices with sizes on the order of L_s were fabricated, enabling the direct detection of the value of L_s in QAH samples. Our results unveil the fundamental length scale that governs the transport behavior of QAH materials.

Abstract

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