上海科技大学知识管理系统

Recently, natural van der Waals heterostructures of (MnBi2Te4)(m)(Bi2Te3)(n)have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states. We systematically investigate both the structural and electronic responses of MnBi(2)Te(4)and MnBi(4)Te(7)to external pressure. In addition to the suppression of antiferromagnetic order, MnBi(2)Te(4)is found to undergo a metal-semiconductor-metal transition upon compression. The resistivity of MnBi(4)Te(7)changes dramatically under high pressure and a non-monotonic evolution of rho(T) is observed. The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime. We find that the bulk and surface states respond differently to pressure, which is consistent with the non-monotonic change of the resistivity. Interestingly, a pressure-induced amorphous state is observed in MnBi2Te4, while two high-pressure phase transitions are revealed in MnBi4Te7. Our combined theoretical and experimental research establishes MnBi(2)Te(4)and MnBi(4)Te(7)as highly tunable magnetic topological insulators, in which phase transitions and new ground states emerge upon compression.