Chen K.H.MLin K.YLien S.WHuang S.WCHIA-KUEN CHENGLin H.YHsu C.-HChang T.-RCheng C.-MMINGHWEI HONGKwo J.2022-12-142022-12-14202224699950https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124454609&doi=10.1103%2fPhysRevB.105.075109&partnerID=40&md5=23f7ca5802c0140a7661418a09fe5cc4https://scholars.lib.ntu.edu.tw/handle/123456789/626182Topological materials, possessing spin-momentum locked topological surface states (TSS), have attracted much interest due to their potential applications in spintronics. α-phase Sn (α-Sn), being one of them, displays enriched topological phases via band-gap engineering through a strain or confinement effect. In this work, we investigated the band evolution of in-plane compressively strained α-Sn(001) thin films on InSb(001) in a wide range of thickness from 3 bilayers (BL) to 370 BL by combining angle-resolved photoemission spectra and first-principles calculations. Gapped surface states evolved to a linearly dispersive TSS at a critical thickness of 6 BL, indicating that the system undergoes a phase transition from topologically trivial to nontrivial. For films thicker than 30 BL, additional Rashba-like surface states (RSS) were identified. These RSS served as preformed TSS in another strain-induced topological phase transition. In thick films, 370-BL α-Sn(001), so as to preclude the confinement effect in thin films, our results were consistent with a Dirac semimetal phase with Dirac nodes located along Formula Presented. This thickness-dependent band-structure study deepens our understanding of topological phase transitions and the evolution of Dirac states. Furthermore, the coexistence of TSS and RSS in a Dirac semimetal α-Sn might significantly enhance the potential for spintronic applications. ©2022 American Physical SocietyAntimony compounds; Calculations; Energy gap; III-V semiconductors; Indium antimonides; Thick films; Thin films; Topology; Angle-resolved photoemission; Band gap engineering; Bi-layer; Confinement effects; Photoemission spectrum; Spin momentum; Strain effect; Thin-films; Topological materials; Topological phase; Surface statesjournal article10.1103/PhysRevB.105.0751092-s2.0-85124454609