Fig. 4: Weak topological insulator state of ZrTe5 and control of its topological phase.
From: Observation and control of the weak topological insulator state in ZrTe5
a In ZrTe5, there are surface states on the side surface, while no surface state exists on the top surface. b–d Topological phase transition in ZrTe5. The WTI state of ZrTe5 can be stabilized by tensile strain (b), and a topological phase transition to DS (c) or even STI (d) can be obtained by compressive strain. There are two band inversions at kb = 0 and kb = π in the WTI state of ZrTe5. The band inversion at kb = 0 is switched by external strain in b–d, while the band inversion at kb = π has no change.
