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arXiv · 1903.10971

Isostructural Mott Transition in 2D honeycomb antiferromagnet V$_{0.9}$PS$_3$

M. J. Coak·S. Son·D. Daisenberger·H. Hamidov·C. R. S. Haines·P. L. Alireza·A. R. Wildes·C. Liu·S. S. Saxena·J. -G. Park
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Abstract

We present the observation of an isostructural Mott insulator-metal transition in van-der-Waals honeycomb antiferromagnet V$_{0.9}$PS$_3$ through high-pressure x-ray diffraction and transport measurements. The MPX$_3$ family of magnetic van-der-Waals materials (M denotes a first row transition metal and X either S or Se) are currently the subject of broad and intense attention, but the vanadium compounds have until this point not been studied beyond their basic properties. We observe insulating variable-range-hopping type resistivity in V$_{0.9}$PS$_3$, with a gradual increase in effective dimensionality with increasing pressure, followed by a transition to a metallic resistivity temperature dependence between 112 and 124 kbar. The metallic state additionally shows a low-temperature upturn we tentatively attribute to the Kondo Effect. A gradual structural distortion is seen between 26-80 kbar, but no structural change at higher pressures corresponding to the insulator-metal transition. We conclude that the insulator-metal transition occurs in the absence of any distortions to the lattice - an isostructural Mott transition in a new class of two-dimensional material, and in strong contrast to the behavior of the other MPX$_3$ compounds.

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M. J. Coak, S. Son, D. Daisenberger, H. Hamidov, C. R. S. Haines, P. L. Alireza, A. R. Wildes, C. Liu, S. S. Saxena, J. -G. Park. 2019-03-26. Isostructural Mott Transition in 2D honeycomb antiferromagnet V$_{0.9}$PS$_3$. https://arxiv.org/abs/1903.10971

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