Electrically tunable quantum confinement of neutral excitons

Exciton localization on p-i-n junctions in two-dimensional crystals

“…In Eq. (1) V eh (r eh ) is the effective 2D interaction given by the Keldysh potential [7][8][9][10][11][12][19][20][21][22],…”

“…[22]. The intrinsic area where the exciton confinement occurs in the experiment [19] has a length of several dozens of nanometers.…”

“…The Stark effect was studied for states in quantum wells [13,14] or quantum dots [15][16][17][18] where the quantum confinement stabilized the weakly bound exciton against dissociation by the electric field. Conversely, the Stark effect for strongly bound excitons in a transition metal dichalcogenide has recently been used to trap the excitons on the electric field at the p-i-n junction [19].…”

“…The purpose of the present work is to describe the exciton confinement in a model of the p-i-n junction by a numerical albeit exact solution of the two-particle problem. The trapping mechanism was explained [19] as due to an effective potential for the exciton that contains a term due to the electric field…”

“…, where F x is the electric field at the junction and α p is the polarizability of the exciton, which for the homogeneous electric field can be determined by the solution of the electron-hole problem in the relative electron-hole coordinates [9,10,19]. The electric field in the junction [19] is not homogeneous and the motion of the center of mass of the exciton does not separate from the eigenproblem in the relative coordinates. Therefore, the center of mass requires treatment on equal rights with the relative electron-hole coordinates which we provide in this work.…”