Experimental and Theoretical Study of Possible Collective Electronic States in Exfoliable Re-Doped NbS2

Amin Azizi; Mehmet Dogan; Jeffrey D Cain; Kyunghoon Lee; Xuanze Yu; Wu Shi; Emily C Glazer; Marvin L Cohen; Alex Zettl

doi:10.1021/acsnano.1c07526

Experimental and Theoretical Study of Possible Collective Electronic States in Exfoliable Re-Doped NbS₂

ACS Nano. 2021 Nov 23;15(11):18297-18304. doi: 10.1021/acsnano.1c07526. Epub 2021 Nov 5.

Authors

Amin Azizi^{1

2}, Mehmet Dogan¹, Jeffrey D Cain^{1

2}, Kyunghoon Lee^{1

2}, Xuanze Yu³, Wu Shi^{1

2

4}, Emily C Glazer¹, Marvin L Cohen¹, Alex Zettl^{1

2}

Affiliations

¹ Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States.
² Kavli Energy NanoScience Institute at the University of California, Berkeley, Berkeley, California 94720, United States.
³ Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, United States.
⁴ Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200438, China.

PMID: 34739204
DOI: 10.1021/acsnano.1c07526

Abstract

Metallic transition-metal dichalcogenides (TMDs) are rich material systems in which the interplay between strong electron-electron and electron-phonon interactions often results in a variety of collective electronic states, such as charge density waves (CDWs) and superconductivity. While most metallic group V TMDs exhibit coexisting superconducting and CDW phases, 2H-NbS₂ stands out with no charge ordering. Further, due to strong interlayer interaction, the preparation of ultrathin samples of 2H-NbS₂ has been challenging, limiting the exploration of presumably rich quantum phenomena in reduced dimensionality. Here, we demonstrate experimentally and theoretically that light substitutional doping of NbS₂ with heavy atoms is an effective approach to modify both interlayer interaction and collective electronic states in NbS₂. Very low concentrations of Re dopants (<1%) make NbS₂ exfoliable (down to monolayer) while maintaining its 2H crystal structure and superconducting behavior. In addition, first-principles calculations suggest that Re dopants can stabilize some native CDW patterns that are not stable in pristine NbS₂.

Keywords: NbS2; atomic structure; charge density waves; interlayer interaction; substitutional doping; superconductivity; transition metal dichalcogenides.