Lan H.-SChang S.TCHEE-WEE LIU2021-09-022021-09-02201724699950https://www.scopus.com/inward/record.uri?eid=2-s2.0-85024400833&doi=10.1103%2fPhysRevB.95.201201&partnerID=40&md5=f46b96f28a0a23a076b12ccf6c9c0039https://scholars.lib.ntu.edu.tw/handle/123456789/580641Electronic structures of Ge1-xSnx alloys (0?x?1) are theoretically studied by the nonlocal empirical pseudopotential method. For relaxed Ge1-xSnx, a topological semimetal is found for x>41% with gapless and band inversion at the Γ point, while there is an indirect-direct band-gap transition at x=8.5%. For strained Ge1-xSnx on a Ge substrate, semimetals with a negative indirect band gap appear for x>43%, and the strained Ge1-xSnx on Ge is always an indirect band-gap semiconductor for x<43%. With appropriate biaxial compressive strains, a topological Dirac semimetal is found with band inversion at Γ and one pair of Dirac cones along the [001] direction. ? 2017 American Physical Society.journal article10.1103/PhysRevB.95.2012012-s2.0-85024400833