Photo-excited states in correlated band insulators

Abstract

We study the photo-excitation dynamics of correlated band insulators, using non-equilibrium dynamical mean-field theory for the ionic Hubbard model. We find two distinct behaviors, depending on the ratio of the on-site interaction $U$ and the bare band gap $\Delta$. For small interactions, the relaxation is characterized by intra-band carrier scattering in relatively rigid bands, leading to a non-thermal intermediate state with separate thermal distributions of electrons and holes. This behavior can be viewed as typical for a band insulator with weak interactions. For larger interaction, on the other hand, we observe a strong modification of the electronic spectrum and a filling-in of the gap after photo-excitation, along with a rapid thermalization of the system. The two behaviors therefore provide a dynamical distinction of a correlated band insulator and a band-insulator, which can differ even when the spectra of the two systems are similar in equilibrium. The crossover happens when the interaction $U$ is comparable to $\Delta$.

arXiv comment10 pages, 9 figures

References in corpus (28)

• Nonequilibrium dynamical mean-field theory and its applications
• Ultrafast switching to a stable hidden topologically protected quantum state in an electronic crystal
• Ultrafast optical spectroscopy of strongly correlated materials and high-temperature superconductors: a non-equilibrium approach
• Theoretical description of time-resolved photoemission spectroscopy: application to pump-probe experiments
• High-spin to low-spin and orbital polarization transitions in multiorbital Mott systems
• Interaction quench in the Hubbard model: Relaxation of the spectral function and the optical conductivity
• Thermalization of a pump-excited Mott insulator
• Can correlations drive a band insulator metallic?
• Quantum critical behavior of the one-dimensional ionic Hubbard model
• Quantum Monte Carlo Study of an Interaction-Driven Band Insulator to Metal Transition
• Novel Phase Between Band and Mott Insulators in Two Dimensions
• Band insulator to Mott insulator transition in a bilayer Hubbard model
• Nature of the insulating phases in the half-filled ionic Hubbard model
• Exact Bond Ordered Ground State for the Transition Between the Band and the Mott Insulator
• Gutzwiller description of non-magnetic Mott insulators: a dimer lattice model
• From Mott Insulator to Band Insulator: A DMFT Study
• Ultra-fast photo-carrier relaxation in Mott insulators with short-range spin correlations
• Role of impact ionization in the thermalization of photo-excited Mott insulators
• Electronic phase transitions in the half-filled ionic Hubbard model
• Correlations in a band insulator
• Evolution of a band insulating phase from a correlated metallic phase
• Nonequilibrium GW+EDMFT: Antiscreening and inverted populations from nonlocal correlations
• The RKKY interactions and the Mott Transition
• Insulating behavior with spin and charge order in the ionic Hubbard model
• Doping a correlated band insulator: A new route to half metallic behaviour
• Band-Insulator-Metal-Mott-Insulator transition in the half--filled $t-t^{\prime }$ ionic-Hubbard chain
• Finite-temperature phase transitions in the ionic Hubbard model
• Magnetic transition in a correlated band insulator

Cited by in corpus (3)

• Quantum Boltzmann equation for strongly correlated systems: comparison to dynamical mean field theory
• Formation of Spatial Patterns by Spin-selective Excitations of Interacting Fermions
• Electron-magnon dynamics triggered by an ultrashort laser pulse: A real-time Dual $GW$ study