Manipulating topological phase transition by strain

2014 ◽  
Vol 70 (2) ◽  
pp. 118-122 ◽  
Author(s):  
Junwei Liu ◽  
Yong Xu ◽  
Jian Wu ◽  
Bing-Lin Gu ◽  
S. B. Zhang ◽  
...  
Keyword(s):  
Phase Transition ◽  
First Principles ◽  
Topological Insulators ◽  
Valence Band Maximum ◽  
Topological Phase ◽  
First Principles Calculations ◽  
Narrow Gap ◽  
Unique Role ◽  
Topological Phase Transition ◽  
Device Applications

First-principles calculations show that strain-induced topological phase transition is auniversalphenomenon in those narrow-gap semiconductors for which the valence band maximum (VBM) and conduction band minimum (CBM) have different parities. The transition originates from the opposite responses of the VBM and CBM, whose magnitudes depend critically on the direction of the applied strain. Our work suggests that strain can play a unique role in tuning the electronic properties of topological insulators for device applications, as well as in the achievement of new topological insulators.

scholarly journals Transformation of the Topological Phase and the Edge Modes of Double-Bilayer Bismuthene with Inter-Bilayer Spacing

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 266 ◽  
Author(s):  
Huanzhi Hu ◽  
Zhibin Shi ◽  
Peng Wang ◽  
Weiping Zhou ◽  
Tai-Chang Chiang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Valence Band ◽  
Conduction Band ◽  
Topological Insulator ◽  
First Principles ◽  
Topological Phase ◽  
First Principles Calculations ◽  
Topological Phase Transition ◽  
Band Inversion ◽  
Band Insulator

The transformations of the topological phase and the edge modes of a double-bilayer bismuthene were investigated with first-principles calculations and Green’s function as the inter-bilayer spacing increased from 0 Å to 10 Å. At a critical spacing of 2 Å, a topological phase transition from a topological insulator to a band insulator resulting from a band inversion between the highest valence band and the second lowest conduction band, was observed, and this was understood based on the particular orbital characters of the band inversion involved states. The edge modes of double-bilayer bismuthene survived the phase transition. When d was 2 Å < d < 4 Å, the interaction between the edge modes of two separated bismuthene bilayers induced an anti-crossing gap and resulted in a trivial band connection. At and beyond 4 Å, the two bilayers behavior decoupled entirely. The results demonstrate the transformability of the topological phase and the edge modes with the inter-bilayer spacing in double-bilayer bismuthene, which may be useful for spintronic applications.

Emergence of topological nodal loops in alkaline-earth hexaborides XB6(X = Ca, Sr, and Ba) under pressure

2017 ◽  
Vol 19 (12) ◽  
pp. 8210-8215 ◽  
Author(s):  
L.-Y. Gan ◽  
R. Wang ◽  
Y. J. Jin ◽  
D. B. Ling ◽  
J. Z. Zhao ◽  
...  
Keyword(s):  
Phase Transition ◽  
First Principles ◽  
Alkaline Earth ◽  
External Pressure ◽  
Topological Phase ◽  
First Principles Calculations ◽  
Topological Phase Transition

Based on first-principles calculations, we report that external pressure can induce a topological phase transition in alkaline-earth hexaborides, XB6(X = Ca, Sr, and Ba).

Strain Induced Topological Phase Transition in Si$_2$Bi$_2$ : First-Principles Study

2021 ◽  
Vol 71 (3) ◽  
pp. 218-224
Author(s):  
Dameul JEONG ◽  
Seungwoo YOO ◽  
Junyeop JEON ◽  
Seung jun LEE ◽  
Young-Kyun KWON*
Keyword(s):  
Phase Transition ◽  
First Principles ◽  
Topological Phase ◽  
First Principles Study ◽  
Topological Phase Transition
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