论文标题
债券破坏诱导的lifshitz过渡中的dirac semimetal $ \ mathbf {val_3} $
Bond-breaking Induced Lifshitz Transition in Robust Dirac Semimetal $\mathbf{VAl_3}$
论文作者
论文摘要
半学中的拓扑电子通常容易受到化学掺杂和环境变化的影响，这限制了它们在将来的电子设备中的潜在应用。在本文中，我们报告说，II型Dirac半学$ \ Mathbf {val_3} $主机出色，可靠的拓扑电子可以忍受化学成分的极端变化。即使在$ \ mathbf {v_ {1-x} ti_xal_3} $ solid解决方案中替换了V原子的大部分部分后，Dirac电子仍然保持完整。这种狄拉克半学状态以$ x = 0.35 $结束，其中lifshitz过渡到$ p $ type琐碎的金属发生。只要粘结轨道被TI取代捐赠的孔完全减小，V-AL键在此转变中就会完全断裂。换句话说，$ \ mathbf {val_3} $中的狄拉克电子受到V-al键的保护，该键是其分子轨道是其粘结引力中心。我们对拓扑半学中电子计数，化学键和电子特性之间的相互关系的理解表明，一种合理的方法来搜索坚固的，化学键值保护的拓扑材料。
Topological electrons in semimetals are usually vulnerable to chemical doping and environment change, which restricts their potential application in future electronic devices. In this paper we report that the type-II Dirac semimetal $\mathbf{VAl_3}$ hosts exceptional, robust topological electrons which can tolerate extreme change of chemical composition. The Dirac electrons remain intact even after a substantial part of V atoms have been replaced in the $\mathbf{V_{1-x}Ti_xAl_3}$ solid solutions. This Dirac semimetal state ends at $x=0.35$ where a Lifshitz transition to $p$-type trivial metal occurs. The V-Al bond is completely broken in this transition as long as the bonding orbitals are fully depopulated by the holes donated from Ti substitution. In other words, the Dirac electrons in $\mathbf{VAl_3}$ are protected by the V-Al bond whose molecular orbital is their bonding gravity center. Our understanding on the interrelations among electron count, chemical bond and electronic properties in topological semimetals suggests a rational approach to search robust, chemical-bond-protected topological materials.
