Formation of Spatial Patterns by Spin-selective Excitations of Interacting Fermions

TL;DR

This paper investigates how spin-selective photoexcitations induce charge and spin density patterns in interacting fermionic systems, using tensor-network simulations to analyze dynamics and decay channels, with implications for experiments in correlated materials and ultracold gases.

Contribution

It introduces a novel approach to generate and analyze spatial patterns via spin-selective excitations in a Hubbard-like system with microstructure, highlighting the role of doublons and comparing to the OISTR mechanism.

Findings

Long-lived charge-density patterns can be induced by spin-selective photoexcitation.

Doublons are identified as the main decay channel for the induced charge pattern.

Spatially periodic patterns are observed in local observables after excitation.

Abstract

We describe the formation of charge- and spin-density patterns induced by spin-selective photoexcitations of interacting fermionic systems in the presence of a microstructure. As an example, we consider a one-dimensional Hubbard-like system with a periodic magnetic microstructure, which has a uniform charge distribution in its ground state, and in which a long-lived charge-density pattern is induced by the spin-selective photoexcitation. Using tensor-network methods, we study the full quantum dynamics in the presence of electron-electron interactions and identify doublons as the main decay channel for the induced charge pattern. Our setup is compared to the OISTR mechanism, in which ultrafast optically induced spin transfer in Heusler and magnetic compounds is associated to the difference of the local density of states of the different elements in the alloys. We find that applying a spin-selective excitation there induces spatially periodic patterns in local observables. Implications for pump-probe experiments on correlated materials and experiments with ultracold gases on optical lattices are discussed.