Integer quantum Hall effect and topological phase transitions in silicene

• Main Authors: Y.L. Liu, G.X. Luo, N. Xu, H.Y. Tian, C.D. Ren
• Format: Article
• Language: English
• Published: Institute for Condensed Matter Physics 2017-12-01
• Series: Condensed Matter Physics
• Subjects: quantum Hall effect; silicene; quantum phase transitions
• Online Access: https://doi.org/10.5488/CMP.20.43701

We numerically investigate the effects of disorder on the quantum Hall effect (QHE) and the quantum phase transitions in silicene based on a lattice model. It is shown that for a clean sample, silicene exhibits an unconventional QHE near the band center, with plateaus developing at ν=0, ±2, ±6,…, and a conventional QHE near the band edges. In the presence of disorder, the Hall plateaus can be destroyed through the float-up of extended levels toward the band center, in which higher plateaus disappear first. However, the center ν=0 Hall plateau is more sensitive to disorder and disappears at a relatively weak disorder strength. Moreover, the combination of an electric field and the intrinsic spin-orbit interaction (SOI) can lead to quantum phase transitions from a topological insulator to a band insulator at the charge neutrality point (CNP), accompanied by additional quantum Hall conductivity plateaus.