The critical role of hot carrier cooling in optically excited structural transitions

Abstract

The hot carrier cooling occurs in most photoexcitation-induced phase transitions (PIPTs), but its role has often been neglected in many theoretical simulations as well as in proposed mechanisms. Here, by including the previously ignored hot carrier cooling in real-time time-dependent density functional theory (rt-TDDFT) simulations, we investigated the role of hot carrier cooling in PIPTs. Taking IrTe2 as an example, we reveal that the cooling of hot electrons from the higher energy levels of spatially extended states to the lower energy levels of the localized Ir-Ir dimer antibonding states strengthens remarkably the atomic driving forces and enhances atomic kinetic energy. These two factors combine to dissolute the Ir-Ir dimers on a timescale near the limit of atomic motions, thus initiating a deterministic kinetic phase transition. We further demonstrate that the subsequent cooling induces nonradiative recombination of photoexcited electrons and holes, leading to the ultrafast recovery of the Ir-Ir dimers observed experimentally. These findings provide a complete picture of the atomic dynamics in optically excited structural phase transitions.

20 pages, 8 figures

Cited by in corpus (6)

• The seeds and homogeneous nucleation of photoinduced nonthermal melting in semiconductors due to self-amplified local dynamic instability
• Uniting the order and disorder dynamics in photoexcited VO2
• Origin of Immediate Damping of Coherent Oscillations in Photoinduced Charge Density Wave Transition
• Dynamic short-range correlation in photoinduced disorder phase transitions
• Laser-induced forces on atoms during ultrafast demagnetization
• Real-Time Out-of-Equilibrium Quantum Dynamics in Disordered Materials