Exciton condensate in bilayer transition metal dichalcogenides: Strong coupling regime

Abstract

Exciton condensation in an electron-hole bilayer system of monolayer transition metal dichalcogenides is analyzed at three different levels of theory to account for screening and quasiparticle renormalization. The large effective masses of the transition metal dichalcogenides place them in a strong coupling regime. In this regime, mean field (MF) theory with either an unscreened or screened interlayer interaction predicts a room temperature condensate. Interlayer and intralayer interactions renormalize the quasiparticle dispersion, and this effect is included in a GW approximation. The renormalization reverses the trends predicted from the unscreened or screened MF theories. In the strong coupling regime, intralayer interactions have a large impact on the magnitude of the order parameter and its functional dependencies on effective mass and carrier density.

Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures

“…3e ) 22 , 28 , 30 . Such repulsive interactions owing to the static electric dipole, combined with the ultralong lifetimes due to the reduced transition dipole, make interlayer excitons a highly promising platform for exploring excitonic Bose–Einstein condensate (BEC) and superconductivity phenomena 31 , 32 , 120 .…”

Coupling of deterministically activated quantum emitters in hexagonal boron nitride to plasmonic surface lattice resonances

“…Particularly, their ability to conform and integrate with other material systems offer unprecedented control over their electronic and optical response [5][6][7][8]. Additionally, these material systems exhibit intriguing quantum phenomena both at the macro scale (e.g., room temperature quantum Hall effect [9], condensates [10], and superconductivity [11]) and nanoscale (e.g., single photon emission from color centers [12,13], and excitons [14][15][16][17]). These features have given the scientific community new ways to explore quantum phenomena while setting the stage for novel devices.…”

Evidence of high-temperature exciton condensation in two-dimensional atomic double layers

“…The weak exciton binding in these systems, however, limits the condensation temperature to ~ 1 K. Although high-temperature exciton condensate has been observed in 1T-TiSe 2 22 , the system based on a three-dimensional semimetal is limited from a future device and configurability perspective. Two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors (MX 2 , M = Mo and W; X = S and Se) with large exciton binding energy (~ 0.5 eV) 23,24 and flexibility in forming van der Waals heterostructures provide an exciting platform for exploring high-temperature exciton condensation and condensate-based applications [9][10][11][12] . The maximum condensation temperature in TMD double layers, limited by exciton ionization in the high-density regime 25 , has been predicted a fraction (~ 10 %) of the exciton binding energy [9][10][11][12] , i.e.…”