Towards superfluidity of dipolar excitons in a TMDC double layer (1705.08179v2)

Abstract: We study formation and superfluidity of dipolar excitons in double layer heterostructures formed by two transition metal dichalcogenide (TMDC) atomically thin layers. Considering screening effects for an electron-hole interaction via the harmonic oscillator approximation for the Keldysh potential, the analytical expressions for the exciton energy spectrum and the mean field critical temperature $T_{c}$ for the superfluidity are obtained. It is shown that binding energies of A excitons are larger than for B excitons. The mean field critical temperature for a two-component dilute exciton system in a TMDC double layer is analyzed and shown that latter is an increasing function of the factor $Q$, determined by the effective masses of A and B excitons and their reduced mass. Comparison of the calculations for $T_{c}$ performed by employing the Coulomb and Keldysh interactions demonstrates the importance of screening effects in TMDC.