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arXiv · 1611.03713

Wigner crystallization in transition metal dichalcogenides: A new approach to correlation energy

M. Zarenia·D. Neilson·B. Partoens·F. M. Peeters
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Abstract

We introduce a new approach for the correlation energy of one- and two-valley two-dimensional electron gas (2DEG) systems. Our approach is based on a random phase approximation at high densities and a classical approach at low densities, with interpolation between the two limits. This approach gives excellent agreement with available Quantum Monte Carlo (QMC) calculations. We employ the two-valley 2DEG model to describe the electron correlations in monolayer transition metal dichalcogenides (TMDs). The zero-temperature transition from a Fermi liquid to a quantum Wigner crystal phase in monolayer TMDs is obtained using density-functional theory within the local-density approximation. Consistent with QMC, we find that electrons crystallize at $r_s=30.5$ in one-valley 2DEG. For two-valleys, we predict Wigner crystallization at $r_s= 29.5$, indicating that valley degeneracy has little effect on the critical $r_s$, in contrast to an earlier claim.

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M. Zarenia, D. Neilson, B. Partoens, F. M. Peeters. 2016-11-11. Wigner crystallization in transition metal dichalcogenides: A new approach to correlation energy. https://doi.org/10.1103/physrevb.95.115438

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