Jump to main content
Jump to site search


Thickness dependent transition from 1T’ to Weyl semimetal phase in ultrathin MoTe2: Electrical transport, Noise and Raman studies

Abstract

Bulk 1T'-MoTe2 shows a structural phase transition from 1T' to Weyl semimetallic (WSM) Td phase at ∽240 K. This phase transition and transport properties in the two phases have not been investigated on ultra-thin crystals. Here we report electrical transport, 1/f noise and Raman studies in ultra-thin 1T'-MoTe2 (∽ 5 to 16 nm thick) field-effect transistors (FETs) devices as a function of temperature. The electrical resistivities for thickness 16 nm and 11 nm show maxima at temperatures 208 K and 178 K, respectively, making a transition from semiconducting to semi-metallic phase, hitherto not observed in bulk samples. Raman frequencies and linewidths for 11nm thick crystal show change around 170 K, attributed to additional contribution to the phonon self-energy due to enhanced electron-phonon interaction in the WSM phase. Further, the resistivity at low-temperature shows an upturn below 20 K along with the maximum in the power spectral density of the low frequency 1/f noise. The latter rules out the metal-insulator transition (MIT) being responsible for the upturn of resistivity below 20 K. The low temperature resistivity follows ρ∝1/T, changing to ρ∝T with increasing temperature supports electron-electron interaction physics at electron-hole symmetric Weyl nodes below 20 K. These observations will pave the way to unravel the properties of WSM state in layered ultra-thin van der Waals materials.

Back to tab navigation

Supplementary files

Article information


Submitted
07 Dec 2019
Accepted
19 Mar 2020
First published
25 Mar 2020

Nanoscale, 2020, Accepted Manuscript
Article type
Paper

Thickness dependent transition from 1T’ to Weyl semimetal phase in ultrathin MoTe2: Electrical transport, Noise and Raman studies

M. kuiri, S. Das, V. S. M. Dharmaraj, A. Das and A. K. Sood, Nanoscale, 2020, Accepted Manuscript , DOI: 10.1039/C9NR10383J

Social activity

Search articles by author

Spotlight

Advertisements