Photo-Induced Phase Transition in Charge Order Systems --Charge Frustration and Interplay with Lattice--

TL;DR

This study investigates how lattice effects influence photo-induced phase transitions in charge frustrated systems, revealing a transition from stripe to 3-fold charge order driven by electron-lattice interactions.

Contribution

It demonstrates the role of lattice vibrations and charge frustration in photo-induced phase transitions, highlighting the cooperative dynamics between electrons and lattice.

Findings

Photo-induced transition from stripe to 3-fold charge order

Threshold optical and electron-lattice coupling values for transition

Distinct dynamics compared to vertical stripe charge order

Abstract

Lattice effects on photo-excited states in interacting charge frustrated system are examined. Real time dynamics in the interacting spinless fermion model on a triangular lattice coupled to lattice vibration are analyzed by applying the exact diagonalization method combined with the classical equation of motion. A photo-induced phase transition from the horizontal stripe-type charge order (CO) to the 3-fold CO occurs through a characteristic intermediate time domain. By analyzing the time evolution in detail, we find that this characteristic dynamics are seen when the electron and lattice sectors are not complementary to each other but show cooperative time evolutions. We also find that there are threshold values in the optical fluorescence and electron-lattice coupling for emergence of the photo-induced 3-fold CO. The dynamics are distinct from those from the vertical stripe-type CO, in which a monotonic CO melting occurs. A scenario of the photo-induced CO phase transition with lattice degree of freedom is presented from a view point of charge frustration.