Real Space Imaging of Topological Edge States in InAs/GaSb and InAs/In<sub><i>x</i></sub>Ga<sub>1-<i>x</i></sub>Sb Quantum Wells.

Kaku, Shigeru; Ando, Tatsuhito; Yoshino, Junji · ACS Nano · 2019

basic_science · Level V

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Abstract

Structure dependent differential tunneling conductance, d<i>I</i>/d<i>V</i>, profiles obtained using scanning tunneling microscopy on both (110)-cleaved surfaces and (001)-growth surfaces in InAs/GaSb and InAs/In<sub><i>x</i></sub>Ga<sub>1-<i>x</i></sub>Sb quantum wells (QWs), which are platforms of two-dimensional topological insulator (2D-TI), clearly demonstrated the edge states formed on the 2D-TI surfaces. The results were confirmed by kp-based electronic structure calculations, which demonstrated that the edge states extended to the 10 nm range from cleaved surfaces generated in the appropriately designed InAs/(In)GaSb QW systems.