Excitations of Intercalated Metal Monolayers in Transition Metal Dichalcogenides

Shiyu Fan; Sabine Neal; Choongjae Won; Jaewook Kim; Deepak Sapkota; Feiting Huang; Junjie Yang; David G Mandrus; Sang-Wook Cheong; Jason T Haraldsen; Janice L Musfeldt

doi:10.1021/acs.nanolett.0c03292

Excitations of Intercalated Metal Monolayers in Transition Metal Dichalcogenides

Nano Lett. 2021 Jan 13;21(1):99-106. doi: 10.1021/acs.nanolett.0c03292. Epub 2020 Dec 2.

Authors

Shiyu Fan¹, Sabine Neal², Choongjae Won³, Jaewook Kim^{4

5

6}, Deepak Sapkota¹, Feiting Huang^{4

5}, Junjie Yang⁷, David G Mandrus^{8

9}, Sang-Wook Cheong^{3

4

5}, Jason T Haraldsen¹⁰, Janice L Musfeldt^{1

2}

Affiliations

¹ Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States.
² Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States.
³ Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea.
⁴ Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States.
⁵ Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, United States.
⁶ Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea.
⁷ Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.
⁸ Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996, United States.
⁹ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
¹⁰ Department of Physics, University of North Florida, Jacksonville, Florida 32224, United States.

PMID: 33264028
DOI: 10.1021/acs.nanolett.0c03292

Abstract

We combine Raman scattering spectroscopy and lattice dynamics calculations to reveal the fundamental excitations of the intercalated metal monolayers in the Fe_xTaS₂ (x = 1/4, 1/3) family of materials. Both in- and out-of-plane modes are identified, each of which has trends that depend upon the metal-metal distance, the size of the van der Waals gap, and the metal-to-chalcogenide slab mass ratio. We test these trends against the response of similar systems, including Cr-intercalated NbS₂ and RbFe(SO₄)₂, and demonstrate that the metal monolayer excitations are both coherent and tunable. We discuss the consequences of intercalated metal monolayer excitations for material properties and developing applications.

Keywords: excitations of intercalated metal monolayers; intercalated transition metal dichalcogenides; structure−property relations involving metal monolayer excitations.