Bond-breaking induced lifshitz transition in robust dirac semimetal VAI3

Yiyuan Liu, Yu Fei Liu, Xin Gui, Cheng Xiang, Hui Bin Zhou, Chuang Han Hsu, Hsin Lin, Tay Rong Chang, Weiwei Xie, Shuang Jia

Research output: Contribution to journalArticlepeer-review

Abstract

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 VAl3 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 V1-xTixAl3solid 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 VAl3are 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.

Original languageEnglish
Pages (from-to)15517-15523
Number of pages7
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number27
DOIs
Publication statusPublished - 2020 Jul 7

All Science Journal Classification (ASJC) codes

  • General

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