Geometry-modulated dipole polarizability of the two-dimensional Mott-Wannier excitons in gate-defined anisotropic quantum dot.

A theoretical investigation on neutral excitons confined to a mono-layer (ML) semiconductor transition metal dichalcogenide (TMDC) materials under the influence of elliptically deformed gate induced confining potential is presented. It has been shown that the anisotropy of the confinement induces the anisotropy of linear response of the system on in-plane external electric field. The linear response is expressed in terms of principal moments of the static dipole polarizability tensor. In this manner the direction-dependent polarizability of the system can be fully controlled by tuning the parameters of gate-induced confining potential. The components of the polarizability tensor are determined using finite-field method based on the exact diagonalization of the electron-hole Hamiltonian including confining potential, Coulomb electron-hole interaction and an external electric field, within effective mass approximation, close to the K-points of the first Brillouin zone of a single-layer MX[Formula: see text] material. The useful scaling relations for energies and dipole polarizabilities as functions of material parameters have been found. The influence of the anisotropy of the confining potential on correlated behavior of charge distribution inside the neutral system has also been demonstrated.