Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2010 Aug 27;105(9):096404. doi: 10.1103/PhysRevLett.105.096404.
Using first-principles calculations within density functional theory, we explore the feasibility of converting ternary half-Heusler compounds into a new class of three-dimensional topological insulators (3DTI). We demonstrate that the electronic structure of unstrained LaPtBi as a prototype system exhibits a distinct band-inversion feature. The 3DTI phase is realized by applying a uniaxial strain along the [001] direction, which opens a band gap while preserving the inverted band order. A definitive proof of the strained LaPtBi as a 3DTI is provided by directly calculating the topological Z2 invariants in systems without inversion symmetry. We discuss the implications of the present study to other half-Heusler compounds as 3DTI, which, together with the magnetic and superconducting properties of these materials, may provide a rich platform for novel quantum phenomena.
我们运用密度泛函理论中的第一性原理计算，探索了将三元半赫斯勒化合物转化为一类新的三维拓扑绝缘体（3DTI）的可能性。我们证明了未受应变的 LaPtBi 作为原型系统的电子结构具有明显的能带反转特征。通过沿[001]方向施加单轴应变，可以实现 3DTI 相，同时保持反转能带序。通过直接在没有反转对称的系统中计算拓扑 Z2 不变量，为受应变的 LaPtBi 作为 3DTI 提供了确凿的证据。我们讨论了本研究对其他半赫斯勒化合物作为 3DTI 的意义，这些化合物以及这些材料的磁性和超导性质，可能为新的量子现象提供了丰富的平台。
