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arXiv · 2310.14202

Controlling spin-orbit coupling to tailor type-II Dirac bands

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
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Abstract

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.

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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. 2023-10-22. Controlling spin-orbit coupling to tailor type-II Dirac bands. https://doi.org/10.1021/acsnano.2c04301

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