Open AccessVisualization of an axion insulating state at the transition between 2 chiral quantum anomalous Hall states
Author(s) -
Monica Allen,
YongTao Cui,
Yue Ma,
Masataka Mogi,
Minoru Kawamura,
Ion Cosma Fulga,
David GoldhaberGordon,
Yoshinori Tokura,
ZhiXun Shen
Publication year - 2019
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.1818255116
Subject(s) - axion , condensed matter physics , quantum hall effect , physics , majorana , topological insulator , magnetic field , chirality (physics) , quantum , quantum computer , quantum phase transition , quantum state , topology (electrical circuits) , phase transition , superconductivity , chiral anomaly , quantum mechanics , fermion , particle physics , electrical engineering , dark matter , engineering , nambu–jona lasinio model
Significance Magnetic topological insulators host chiral dissipationless edge modes, which mimic quantum Hall states but persist in the absence of a magnetic field. We use microwave impedance microscopy, which characterizes the local complex conductivity of a material, to provide direct visualization of these edge states and monitor their evolution across a magnetic-field–induced phase transition. The resulting images reveal an insulating state, which exhibits a distinct geometry of current flow, at the boundary between 2 quantum anomalous Hall (QAH) states with opposite chirality. Due to their immunity to backscattering, the edge currents present in the QAH regime provide a promising platform for future investigations of chiral Majorana modes, key building blocks for a topological quantum computer.
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