Curvature induced quantum phase transitions in an electron-hole system

Zhuo Bin Siu; Jian-Yuan Chang; Seng Ghee Tan; Mansoor B A Jalil; Ching-Ray Chang

doi:10.1038/s41598-018-34903-9

Curvature induced quantum phase transitions in an electron-hole system

Sci Rep. 2018 Nov 7;8(1):16497. doi: 10.1038/s41598-018-34903-9.

Authors

Zhuo Bin Siu¹, Jian-Yuan Chang², Seng Ghee Tan^{3

4}, Mansoor B A Jalil⁵, Ching-Ray Chang^{2

6}

Affiliations

¹ Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore. elesiuz@nus.edu.sg.
² Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
³ Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
⁴ Department of Optoelectric Physics, Chinese Culture University, Taipei, 11114, Taiwan.
⁵ Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
⁶ Center for Theoretical Physics, National Taiwan University, Taipei, 10617, Taiwan.

Abstract

In this work, we study the effect of introducing a periodic curvature on nanostructures, and demonstrate that the curvature can lead to a transition from a topologically trivial state to a non-trivial state. We first present the Hamiltonian for an arbitrarily curved nanostructure, and introduce a numerical scheme for calculating the bandstructure of a periodically curved nanostructure. Using this scheme, we calculate the bandstructure for a sinusoidally curved two-dimensional electron gas. We show that the curvature can lead to a partner switching reminiscent of a topological phase transition at the time reversal invariant momenta. We then study the Bernevig-Hughes-Zhang (BHZ) Hamiltonian for a two-dimensional quantum well. We show that introducing a curvature can lead to the emergence of topological surface states.

Abstract

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