Exciton–phonon coupling strength in single-layer MoSe2 at room temperature

Abstract

Single-layer transition metal dichalcogenides are at the center of an ever increasing research effort both in terms of fundamental physics and applications. Exciton–phonon coupling plays a key role in determining the (opto)electronic properties of these materials. However, the exciton–phonon coupling strength has not been measured at room temperature. Here, we use two-dimensional micro-spectroscopy to determine exciton–phonon coupling of single-layer MoSe2. We detect beating signals as a function of waiting time induced by the coupling between A excitons and A′1 optical phonons. Analysis of beating maps combined with simulations provides the exciton–phonon coupling. We get a Huang–Rhys factor ~1, larger than in most other inorganic semiconductor nanostructures. Our technique offers a unique tool to measure exciton–phonon coupling also in other heterogeneous semiconducting systems, with a spatial resolution ~260 nm, and provides design-relevant parameters for the development of optoelectronic devices.

Time-linear scaling NEGF methods for real-time simulations of interacting electrons and bosons. II. Dynamics of polarons and doublons

“…It is well known that phonons hybridize with a variety of electronic excitations: plasmons [53][54][55], excitons [16,56,57], polaritons [58], collective amplitude modes in superconductors [59]. Much less is known about the coupling of doublons and phonons, being a topic of current intense investigations [60].…”

Real-time non-adiabatic dynamics in the one-dimensional Holstein model: Trajectory-based vs exact methods

“…13 Here, such excitations can couple to electrons and influence the electronic properties. For example, exciton-phonon coupling [17][18][19][20][21][22] in semiconductors affects exciton mobilities, the phononbottleneck mechanism reduces energy loss of hot carriers, [23][24][25][26][27] and phonon-magnon scattering 28,29 induced by electronphonon coupling can lead to ultrafast demagnetization, 30 to mention a few examples. Clearly, there is an increasing interest in the theoretical description of such multi-component systems involving bosons, also in view of recent ultrafast dynamics experiments, [31][32][33] where, for example, light excitations in electron-phonon coupled systems have been claimed to en-hance superconductivity [34][35][36][37][38][39][40] or where phase transitions to a charge-density-wave phase [41][42][43] or a metal-insulator structural phase transition 44 can be driven.…”

A Reciprocal-Space Formulation of Surface Hopping

“…The recent years have seen a surge in interest in crystalline materials where band-like electronic conductance coexists with strong electron-phonon interactions, examples of which include hybrid metal-halide perovskites [1][2][3] and monolayer transition-metal dichalcogenides. [4][5][6][7][8] Few of the theoretical methods currently available are able to efficiently describe lattice-based electron-phonon couplings beyond the perturbative regime, [9][10][11] hampering our ability to unravel the nonequilibrium behavior of such materials.…”