Dynamic polarizability of low-dimensional excitons
arXiv:2110.14399 · doi:10.1103/PhysRevB.104.155414
Abstract
Excitons in low-dimensional materials behave mathematically as confined hydrogen atoms. An appealing unified description of confinement in quantum wells or wires, etc., is found by restricting space to a fractional dimension 1 < D <= 3 serving as an adjustable parameter. We compute the dynamic polarizability of D-dimensional excitons in terms of discrete and continuum oscillator strengths. Analyzing exact sum rules, we show that continuum contributions are increasingly important in low dimensions. The dynamical responses of excitons in various dimensions are compared. Finally, an exact and compact closed-form expression for the dynamic polarizability is found. This completely general formula takes D as input and provides exact results for arbitrary frequency.
References in corpus (9)
- Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
- Valley-selective optical Stark effect in monolayer WS2
- Ultrafast Generation of Pseudo-magnetic Field for Valley Excitons in WSe2 Monolayers
- Simple Screened Hydrogen Model of Excitons in Two-Dimensional Materials
- Dissociation of two-dimensional excitons in monolayer WSe2
- The Coulomb interaction in monolayer transition-metal dichalcogenides
- Stark effect in low-dimension hydrogen
- Long-range interactions of hydrogen atoms in excited states. I. 2S-1S interactions and Dirac-delta perturbations
- Microscopic theory of the polarizability of transition metal dichalcogenides excitons: Application to WSe2