Charge-order-enhanced capacitance in semiconductor moiré superlattices

Abstract

Van der Waals moiré materials have emerged as a highly controllable platform to study the electronic correlation phenomena. In particular, robust correlated insulating states have recently been discovered at both integer and fractional filling factors of the semiconductor moiré systems. Here, we reveal the thermodynamic properties of these states by measuring the gate capacitance of MoSe2/WS2 moiré superlattices. We observe a series of incompressible states for filling factor 0 - 8 and anomalously large capacitance (nearly 60% above the device's geometrical capacitance) in the intervening compressible regions. The anomalously large capacitance is most pronounced at small filling factor, below the melting temperature of the charge-ordered states, and for small sample-gate separation. It is a manifestation of the device-geometry-dependent Coulomb interaction between electrons and phase mixing of the charge-ordered states. We have further extracted the thermodynamic gap of the correlated insulating states and the entropy of the capacitive device. The results not only establish capacitance as a powerful probe of the correlated states in semiconductor moiré systems, but also demonstrate control of the extended Coulomb interaction in these materials via sample-gate coupling.

References in corpus (3)

• Observation of Moiré Excitons in WSe2/WS2 Heterostructure Superlattices
• Entropic evidence for a Pomeranchuk effect in magic angle graphene
• Generalized Wigner crystallization in moiré materials

Cited by in corpus (23)

• Quantum anomalous Hall effect from intertwined moiré bands
• Observation of integer and fractional quantum anomalous Hall effects in twisted bilayer MoTe2
• Continuous Mott transition in semiconductor moiré superlattices
• Tunable bilayer Hubbard model physics in twisted WSe2
• Mapping twist-tuned multiband topology in bilayer WSe${}_2$
• Frustrated magnetic interactions in a Wigner-Mott insulator
• Gate-tunable heavy fermion quantum criticality in a moiré Kondo lattice
• Competing magnetic states in transition metal dichalcogenide moiré materials
• Tunable spin and valley excitations of correlated insulators in $\Gamma$-valley moiré bands
• Hofstadter states and reentrant charge order in a semiconductor moiré lattice
• Field-induced hybridization of moiré excitons in MoSe${}_2$/WS${}_2$ heterobilayers
• Quantum oscillations in 2D insulators induced by graphite gates
• Interaction range and temperature dependence of symmetry breaking in strongly correlated two-dimensional moiré transition metal dichalcogenide bilayers
• Observation of an electronic microemulsion phase emerging from a quantum crystal-to-liquid transition
• Quantum Wigner molecules in moiré materials
• Doping a Wigner-Mott insulator: Exotic charge orders in transition-metal dichalcogenide moiré heterobilayers
• Mott insulators in moiré transition metal dichalcogenides at fractional fillings: Slave-rotor mean-field theory
• Time-Domain Signatures of Distinct Correlated Insulators in a Moiré Superlattice
• Optical readout of the chemical potential of two-dimensional electrons
• Quantum melting of generalized electron crystal in twisted bilayer MoSe2
• Interlayer Fermi polarons of excited exciton states in quantizing magnetic fields
• Interplay between topology and electron-electron interactions in the moiré MoTe${}_2$/WSe${}_2$ heterobilayer
• Magnetism from multiparticle ring exchange in moiré Wigner crystals