TY - JOUR
T1 - Emergent and Tunable Topological Surface States in Complementary Sb/Bi2Te3and Bi2Te3/Sb Thin-Film Heterostructures
AU - Li, Yao
AU - Bowers, John W.
AU - Hlevyack, Joseph A.
AU - Lin, Meng Kai
AU - Chiang, Tai Chang
N1 - Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/6/28
Y1 - 2022/6/28
N2 - Epitaxial thin-film heterostructures offer a versatile platform for realizing topological surface states (TSSs) that may be emergent and/or tunable by tailoring the atomic layering in the heterostructures. Here, as an experimental demonstration, Sb and Bi2Te3 thin films with closely matched inplane lattice constants are chosen to form two complementary heterostructures: Sb overlayers on Bi2Te3 (Sb/Bi2Te3) and Bi2Te3 overlayers on Sb (Bi2Te3/Sb), with the overlayer thickness as a tuning parameter. In the bulk form, Sb (a semimetal) and Bi2Te3 (an insulator) both host TSSs with the same topological order but substantially different decay lengths and dispersions, whereas ultrathin Sb and Bi2Te3 films by themselves are fully gapped trivial insulators. Angle-resolved photoemission band mappings, aided by theoretical calculations, confirm the formation of emergent TSSs in both heterostructures. The energy position of the topological Dirac point varies as a function of overlayer thickness, but the variation is non-monotonic, indicating nontrivial effects in the formation of topological heterostructure systems. The results illustrate the rich physics of engineered composite topological systems that may be exploited for nanoscale spintronics applications.
AB - Epitaxial thin-film heterostructures offer a versatile platform for realizing topological surface states (TSSs) that may be emergent and/or tunable by tailoring the atomic layering in the heterostructures. Here, as an experimental demonstration, Sb and Bi2Te3 thin films with closely matched inplane lattice constants are chosen to form two complementary heterostructures: Sb overlayers on Bi2Te3 (Sb/Bi2Te3) and Bi2Te3 overlayers on Sb (Bi2Te3/Sb), with the overlayer thickness as a tuning parameter. In the bulk form, Sb (a semimetal) and Bi2Te3 (an insulator) both host TSSs with the same topological order but substantially different decay lengths and dispersions, whereas ultrathin Sb and Bi2Te3 films by themselves are fully gapped trivial insulators. Angle-resolved photoemission band mappings, aided by theoretical calculations, confirm the formation of emergent TSSs in both heterostructures. The energy position of the topological Dirac point varies as a function of overlayer thickness, but the variation is non-monotonic, indicating nontrivial effects in the formation of topological heterostructure systems. The results illustrate the rich physics of engineered composite topological systems that may be exploited for nanoscale spintronics applications.
KW - Topological insulator
KW - emergent electronic structure
KW - tunable Dirac surface state
KW - ultrathin film
KW - van der Waals heterostructure
UR - http://www.scopus.com/inward/record.url?scp=85134848311&partnerID=8YFLogxK
U2 - 10.1021/acsnano.2c04639
DO - 10.1021/acsnano.2c04639
M3 - 期刊論文
C2 - 35699943
AN - SCOPUS:85134848311
SN - 1936-0851
VL - 16
SP - 9953
EP - 9959
JO - ACS Nano
JF - ACS Nano
IS - 6
ER -