Expeditious computation of nonlinear optical properties of arbitrary order with native electronic interactions in the time domain

Abstract

We adapted a recently proposed framework to characterize the optical response of interacting electrons in solids in order to expedite its computation without compromise in accuracy at the microscopic level. Our formulation is based on reliable parametrizations of Hamiltonians and Coulomb interactions, which allows economy and flexibility in obtaining response functions. It is suited to computing the optical response to fields of arbitrary temporal shape and strength, to arbitrary order in the field, and natively accounts for excitonic effects. We demonstrate the approach by computing the frequency-dependent susceptibilities of MoS 2 and hexagonal BN monolayers up to the third harmonic. Grounded on a generic nonequilibrium many-body perturbation theory, this framework allows extensions to handle generic interaction models or to describe electronic processes taking place at ultrafast time scales.

Simulating Vibronic Spectra without Born–Oppenheimer Surfaces

“…Furthermore, we expect that MTEF-kick will improve in accuracy for periodic systems, as changes in the electronic configuration are often to likely produce smaller changes in the nuclear forces than in molecular hydrogen. This makes this method interesting to pursue in periodic systems in particular, where there is a dearth of theoretical frameworks for ab initio , nonpertubrative electron–nuclear coupling . Work in this direction is in progress, as is the implementation of the ICWF method within an ab initio framework for molecular and periodic systems.…”

“…This makes this method interesting to pursue in periodic systems in particular, where there is a dearth of theoretical frameworks for ab initio, nonpertubrative electron−nuclear coupling. 49 Work in this direction is in progress, as is the implementation of the ICWF method within an ab initio framework for molecular and periodic systems.…”

Theoretical Approach for Electron Dynamics and Ultrafast Spectroscopy (EDUS)

“…This involves a sum over the k-space of the density matrix times the Coulomb interaction W nk′mk,mk′nk , whose definition is a two-particle integral (eq 7). For Bloch wave functions ψ n,k (r) = e ik•r u n,k (r), the Coulomb interaction can also be expressed as 35…”

“…This involves a sum over the k -space of the density matrix times the Coulomb interaction W n k ′ m k , m k ′ n k , whose definition is a two-particle integral (eq ). For Bloch wave functions ψ n , k ( r ) = e i k · r u n , k ( r ), the Coulomb interaction can also be expressed as W n boldk false′ boldmk , l boldk false′ boldjk = prefix∑ boldG [ I jk , n k ′ G ] * I boldmk , l boldk false′ boldG 0.25em V boldk false′ − boldk + boldG where G is a sum over reciprocal lattice vectors, V k is the Fourier transform of the Coulomb energy V ( r ), and .25ex2ex I boldmk , m false′ boldk false′ boldG ≡ prefix∫ normald 3 r 0.25em u boldmk * ( r ) u m false′ boldk false′ false( …”

Simulating Vibronic Spectra without Born-Oppenheimer Surfaces

“…This makes this method interesting to pursue in periodic systems in particular, where there is a dearth of theoretical frameworks for ab initio, nonpertubrative electron-nuclear coupling. 48 Work in this direction is in progress, as is the implementation of the ICWF method within an ab initio framework for molecular and periodic systems.…”