Nano-infrared imaging of metal insulator transition in few-layer 1T-TaS2

Among the family of transition metal dichalcogenides, 1T-TaS2 stands out for several peculiar physical properties including a rich charge density wave phase diagram, quantum spin liquid candidacy and low temperature Mott insulator phase. As 1T-TaS2 is thinned down to the few-layer limit, interesting...

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Bibliographic Details
Main Authors: Zhang Songtian S., Rajendran Anjaly, Chae Sang Hoon, Zhang Shuai, Pan Tsai-Chun, Hone James C., Dean Cory R., Basov D. N.
Format: Article
Language:English
Published: De Gruyter 2023-03-01
Series:Nanophotonics
Subjects:
Online Access:https://doi.org/10.1515/nanoph-2022-0750
Description
Summary:Among the family of transition metal dichalcogenides, 1T-TaS2 stands out for several peculiar physical properties including a rich charge density wave phase diagram, quantum spin liquid candidacy and low temperature Mott insulator phase. As 1T-TaS2 is thinned down to the few-layer limit, interesting physics emerges in this quasi 2D material. Here, using scanning near-field optical microscopy, we perform a spatial- and temperature-dependent study on the phase transitions of a few-layer thick microcrystal of 1T-TaS2. We investigate encapsulated air-sensitive 1T-TaS2 prepared under inert conditions down to cryogenic temperatures. We find an abrupt metal-to-insulator transition in this few-layer limit. Our results provide new insight in contrast to previous transport studies on thin 1T-TaS2 where the resistivity jump became undetectable, and to spatially resolved studies on non-encapsulated samples which found a gradual, spatially inhomogeneous transition. A statistical analysis suggests bimodal high and low temperature phases, and that the characteristic phase transition hysteresis is preserved down to a few-layer limit.
ISSN:2192-8606
2192-8614