Controlling Spin–Orbit Coupling to Tailor Type-II Dirac Bands

• DOI: 10.1021/acsnano.2c04301
• Publication Date: 2022-07-15T14:43:36Z
• Authors: Nguyen Huu Lam; Phuong Lien Nguyen; Byoung Ki Choi; Trinh Thi Ly; Ganbat Duvjir; Tae Gyu Rhee; Yong Jin Jo; Tae Heon Kim; Chris Jozwiak; Aaron Bostwick; Eli Rotenberg; Younghun Hwang; Young Jun Chang; Jaekwang Lee; Jungdae Kim
• Keywords: Condensed Matter - Materials Science; Condensed Matter - Strongly Correlated Electrons; 0303 health sciences; 03 medical and health sciences; Condensed Matter - Mesoscale and Nanoscale Physics; Strongly Correlated Electrons (cond-mat.str-el); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences

NiTe2, a type-II Dirac semimetal with strongly tilted Dirac band, has been explored extensively to understand its intriguing topological properties. Here, using density-functional theory (DFT) calculations, we report that the strength of spin-orbit coupling (SOC) in NiTe2 can be tuned by Se substitution. This results in negative shifts of the bulk Dirac point (BDP) while preserving the type-II Dirac band. Indeed, combined studies using scanning tunneling spectroscopy (STS) and angle-resolved photoemission spectroscopy (ARPES) confirm that the BDP in the NiTe2-xSex alloy moves from +0.1 eV (NiTe2) to -0.3 eV (NiTeSe) depending on the Se concentrations, indicating the effective tunability of type-II Dirac fermions. Our results demonstrate an approach to tailor the type-II Dirac band in NiTe2 by controlling the SOC strength via chalcogen substitution. This approach can be applicable to different types of topological materials.<br/>25 pages, 4 figures<br/>