Non-equilibrium Bethe-Salpeter equation for transient photo-absorption spectroscopy

Abstract

In this work we propose an accurate first-principle approach to calculate the transient photo--absorption spectrum measured in Pump\&\,Probe experiments. We formulate a condition of {\em adiabaticity} and thoroughly analyze the simplifications brought about by the fulfillment of this condition in the non--equilibrium Green's function (NEGF) framework. Starting from the Kadanoff-Baym equations we derive a non--equilibrium Bethe--Salpeter equation (BSE) for the response function that can be implemented in most of the already existing {\em ab--initio} codes. In addition, the {\em adiabatic} approximation is benchmarked against full NEGF simulations in simple model hamiltonians, even under extreme, nonadiabatic conditions where it is expected to fail. We find that the non--equilibrium BSE is very robust and captures important spectral features in a wide range of experimental configurations.

13 pages, 5 captioned figures

References in corpus (5)

• {\it Ab--initio} finite temperature excitons
• Simulating pump-probe photo-electron and absorption spectroscopy on the attosecond time-scale with time-dependent density-functional theory
• Time-resolved spectroscopy in time dependent density functional theory: An exact condition
• First-principles nonequilibrium Green's function approach to transient photoabsorption: Application to atoms
• Some Exact Properties of the Nonequilibrium Response Function for Transient Photoabsorption

Cited by in corpus (29)

• Charge-Transfer in Time-Dependent Density Functional Theory
• Ab initio calculations of ultra-short carrier dynamics in 2D materials: valley depolarization in single-layer WSe${}_2$
• First-principles approach to excitons in time-resolved and angle-resolved photoemission spectra
• Real-time GW: Toward an ab initio description of the ultrafast carrier and exciton dynamics in two-dimensional materials
• Non equilibrium optical properties in semiconductors from first--principles: a combined theoretical and experimental study of bulk silicon
• Charge separation in donor-C60 complexes with real-time Green's functions: The importance of nonlocal correlations
• Ultrafast nonequilibrium evolution of excitonic modes in semiconductors
• Spin States Protected from Intrinsic Electron-Phonon-Coupling Reaching 100 ns Lifetime at Room Temperature in MoSe${}_2$
• CHEERS: A tool for Correlated Hole-Electron Evolution from Real-time Simulations
• Phonon-assisted luminescence in defect centers from many-body perturbation theory
• Photoinduced dynamics of organic molecules using nonequilibrium Green's functions with second-Born, $GW$, $T$-matrix and three-particle ladder correlations
• Exciton-Driven Renormalization of Quasiparticle Band Structure in Monolayer MoS2
• An ab-initio approach to describe coherent and non-coherent exciton dynamics
• Exciton-phonon interaction calls for a revision of the "exciton" concept
• Studies of Spuriously Shifting Resonances in Time-dependent Density Functional Theory
• Excitons and carriers in transient absorption and time-resolved ARPES spectroscopy: an abinitio approach
• Adiabatic Preparation of a Correlated Symmetry-Broken Initial State with the Generalized Kadanoff--Baym Ansatz
• Phonon-assisted processes in the ultraviolet transient optical response of graphene
• Theory of coherent phonons coupled to excitons
• A Snapshot of Time-Dependent Density-Functional Theory
• Quantum transport under AC drive from the leads : A Quantum Master Equation approach
• Nonequilibrium susceptibility in photoinduced Floquet states
• Expeditious computation of nonlinear optical properties of arbitrary order with native electronic interactions in the time domain
• Time-resolved spectroscopy at surfaces and adsorbate dynamics: insights from a model-system approach
• Excitonic Bloch equations from first principles
• Coherence and de-coherence in the Time-Resolved ARPES of realistic materials: an ab-initio perspective
• The dissection algorithm for the second-Born self-energy
• Linear and Nonlinear Optical Properties of Molecules from Real-Time Propagation Based on the Bethe-Salpeter Equation
• First-principles approach to ultrafast pump-probe spectroscopy in solids