Melting of electronic and excitonic crystals in 2D semiconductor moiré patterns: a perspective from the Lindemann criterion

Abstract

Using the Lindemann criterion, we analyzed the quantum and thermal melting of electronic/excitonic crystals recently discovered in two-dimensional (2D) semiconductor moiré patterns. We show that the finite 2D screening of the atomically thin material can suppress (enhance) the inter-site Coulomb (dipolar) interaction strength, thus inhibits (facilitates) the formation of the electronic (excitonic) crystal. Meanwhile, a strong enough moiré confinement is found to be essential for realizing the crystal phase with a wavelength near 10 nm or shorter. From the calculated Lindemann ratio which quantifies the fluctuation of the site displacement, we estimate that the crystal will melt into a liquid above a critical temperature ranging from several tens Kelvin to above 100 K (depending on the system parameters).

References in corpus (10)

• Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
• Moiré excitons: from programmable quantum emitter arrays to spin-orbit coupled artificial lattices
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Cited by in corpus (5)

• Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Stability of Wigner crystals and Mott insulators in twisted moiré structures
• Chiral phonons of honeycomb-type bilayer Wigner crystals
• Interaction enhanced inter-site hoppings for holons and interlayer exciton insulators in moiré correlated insulators