Using Nonequilibrium Dynamics to Probe Competing Orders in a Mott-Peierls System

摘要

Competition between ordered phases, and their associated phase transitions,are significant in the study of strongly correlated systems. Here we examineone aspect, the nonequilibrium dynamics of a photoexcited Mott-Peierls system,using an effective Peierls-Hubbard model and exact diagonalization. Near atransition where spin and charge become strongly intertwined, we observeanti-phase dynamics and a coupling-strength-dependent suppression orenhancement in the static structure factors. The renormalized bosonicexcitations coupled to a particular photoexcited electron can be extracted,which provides an approach for characterizing the underlying bosonic modes. Theresults from this analysis for different electronic momenta show an unevensoftening due to a stronger coupling near $k_F$. This behavior reflects thestrong link between the fermionic momenta, the coupling vertices, andultimately the bosonic susceptibilities when multiple phases compete for theground state of the system.