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.
@article{arxiv.2310.14202,
title = {Controlling spin-orbit coupling to tailor type-II Dirac bands},
author = {Nguyen Huu Lam and Phuong Lien Nguyen and Byoung Ki Choi and Trinh Thi Ly and Ganbat Duvjir and Tae Gyu Rhee and Yong Jin Jo and Tae Heon Kim and Chris Jozwiak and Aaron Bostwick and Eli Rotenberg and Younghun Hwang and Young Jun Chang and Jaekwang Lee and Jungdae Kim},
journal= {arXiv preprint arXiv:2310.14202},
year = {2023}
}