The tunability of topological surface states and controllable opening of the Dirac gap are of great importance to the application of topological materials. In topological crystalline insulators (TCIs), crystal symmetry and topology of electronic bands intertwine to create topological surface states and thus the Dirac gap can be modulated by symmetry breaking structural changes of lattice. By transport measurement on heterostructures composed of p-type topological crystalline insulator SnTe and n-type conventional semiconductor PbTe, here we show a giant linear magnetoresistance (up to 2150% under 14 T at 2 K) induced by the Dirac Fermions at the PbTe/SnTe interface. In contrast, PbTe/SnTe samples grown at elevated temperature exhibit a cubic-to-rhombohedral structural phase transition of SnTe lattice below 100 K and weak antilocalization effect. Such distinctive magneto-resistance behavior is attributed to the broken mirror symmetry and gapping of topological surface states. Our work provides a promising application for future magneto-electronics and spintronics based on TCI heterostructures.
The effect of hydrostatic pressure and uniaxial strain on the electronic structure of Pb$_{\text{1-x}}$Sn$_{\text{x}}$Te
在密度泛函理论的框架下，采用相对论Korringa-Kohn-Rostoker格林函数方法研究了Pb $_{1-x}$ Sn $_{x}$ Te的电子结构.对于所有浓度的$x$，Pb $_{1-x}$ Sn $_{x}$ Te是具有窄带隙的直接半导体。与纯碲化铅相反，碲化锡显示出接近费米能的倒带特性。它将被证明，这种特殊的性能可以被调谐，第一，通过合金化PbTe和SnTe，第二，通过施加静水压力或单轴应变。此外，在规则带隙和反转带隙之间切换所需的应变的大小可以通过合金组成来调节。因此，存在Pb $_{1-x}$ Sn $_{x}$ Te用于自旋电子学应用的潜在用途范围。
Pentagonal nanowires from topological crystalline insulators: a platform for intrinsic core-shell nanowires and higher-order topology
International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences（波兰科学院物理研究所磁顶国际研究中心）；Institute for Advanced Study, Shenzhen University（深圳大学高等研究院）；Consiglio Nazionale delle Ricerche (CNR-SPIN), Unitá di Ricerca presso Terzi c/o Universitá “G. D’Annunzio”（意大利国家研究委员会（CNR-SPIN）第泽齐研究单元/阿布鲁佐大学）
