Predication of topological states in the allotropes of group-Ⅳ elements

• 作者: Chengyong Zhong
• 来源期刊: 物理学前沿
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: Condensed Matter&Materials Physics
• 页码范围: 115-122
• 页数: 8页
• 语种: 英文

摘要

Three-dimensional(3D)topological insulators(TIs)have been studied for approximately fifteen years,but those made from group-Ⅳ elements,especially Ge and Sn,seem particularly attractive owing to their nontoxicity,sizable intrinsic spin-orbit coupling(SOC)strength and natural compatibility with the current semiconductor industry.However,group-Ⅳ elemental TIs have rarely been reported,except for the low temperature phase of α-Sn under strain.Here,based on first-principles calculations,we propose new allotropes of Ge and Sn,named T5-Ge/Sn,as desirable TIs.These new allotropes are also highly anisotropic Dirac semimetals if the SOC is turned off.To the best of our knowledge,T5-Ge/Sn are the first 3D allotropes of Ge/Sn that possess topological states in their equilibrium states at room temperature.Additionally,their isostructures of C and Si are metastable indirect and direct semiconductors.Our work not only reveals two promising TIs,but more profoundly,we justify the advantages of group-Ⅳ elements as topological quantum materials(TQMs)for fundamental research and potential practical applications,and thus reveal a new direction in the search for desirable TQMs.