Anharmonicity Reveals the Tunability of the Charge Density Wave Orders in Monolayer VSe2

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Nano Letters, Volume 23, issue 5
VSe2 is a layered compound that has attracted great attention due to its proximity to a ferromagnetic state that is quenched by its charge density wave (CDW) phase. In the monolayer limit, unrelated experiments have reported different CDW orders with different transition temperatures, making this monolayer very controversial. Here we perform first-principles nonperturbative anharmonic phonon calculations in monolayer VSe2 in order to estimate the CDW order and the corresponding transition temperature. They reveal that monolayer VSe2 develops two independent charge density wave orders that compete as a function of strain. Variations of only 1.5% in the lattice parameter are enough to stabilize one order or the other. Moreover, we analyze the impact of external Lennard-Jones interactions, showing that these can act together with anharmonicity to suppress the CDW orders.
Funding Information: We acknowledge the computational resources provided by the CESGA and the Aalto Science-IT project. A.O.F. acknowledges the financial support received through the Academy of Finland Project No. 349696. J.D. thanks the Department of Education of the Basque Government for a predoctoral fellowship (Grant No. PRE-2020-1-0220). We thank the Ministry of Science and Education of Spain for financial support through the projects PGC2018-101334-A-C22, GC2018-101334-B-C21, PID2021-122609NB-C22. I.E. acknowledges funding from the Department of Education, Universities and Research of the Eusko Jaurlaritza, and the University of the Basque Country UPV/EHU (Grant No. IT1527-22). Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.
2D materials, anharmonic effects, charge density wave, competing orders, strain, van der Waals interactions
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Fumega , A O , Diego , J , Pardo , V , Blanco-Canosa , S & Errea , I 2023 , ' Anharmonicity Reveals the Tunability of the Charge Density Wave Orders in Monolayer VSe 2 ' , Nano Letters , vol. 23 , no. 5 , pp. 1794–1800 .