Doping controlled Fano resonance in bilayer 1T�-ReS2: Raman experiments and first-principles theoretical analysis

Das, S and Prasad, S and Chakraborty, B and Jariwala, B and Shradha, S and Muthu, DVS and Bhattacharya, A and Waghmare, UV and Sood, AK (2021) Doping controlled Fano resonance in bilayer 1T�-ReS2: Raman experiments and first-principles theoretical analysis. In: Nanoscale, 13 (2). pp. 1248-1256.

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Abstract

In the bilayer ReS2 channel of a field-effect transistor (FET), we demonstrate using Raman spectroscopy that electron doping (n) results in softening of frequency and broadening of linewidth for the in-plane vibrational modes, leaving the out-of-plane vibrational modes unaffected. The largest change is observed for the in-plane Raman mode at �151 cm-1, which also shows doping induced Fano resonance with the Fano parameter 1/q = -0.17 at a doping concentration of �3.7 � 1013 cm-2. A quantitative understanding of our results is provided by first-principles density functional theory (DFT), showing that the electron-phonon coupling (EPC) of in-plane modes is stronger than that of out-of-plane modes, and its variation with doping is independent of the layer stacking. The origin of large EPC is traced to 1T to 1T� structural phase transition of ReS2 involving in-plane displacement of atoms whose instability is driven by the nested Fermi surface of the 1T structure. Results are compared with those of the isostructural trilayer ReSe2. This journal is © The Royal Society of Chemistry.

Item Type:	Journal Article
Publication:	Nanoscale
Publisher:	Royal Society of Chemistry
Additional Information:	The copyright of this article belongs to Royal Society of Chemistry
Keywords:	Density functional theory; Electron-phonon interactions; Field effect transistors; Resonance, Doping concentration; Electron phonon couplings; First-principles density functional theory; In-plane displacement; Out-of-plane modes; Raman experiments; Structural phase transition; Vibrational modes, Rhenium compounds
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 Feb 2021 10:52
Last Modified:	22 Feb 2021 10:52
URI:	http://eprints.iisc.ac.in/id/eprint/67939

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