Quantum spin pumping at fractionally quantized magnetization state for a system with competing exchange interactions

TL;DR

This paper investigates quantum spin pumping in a spin-1/2 chain with competing interactions, demonstrating how a modulated potential can induce spin transport at specific fractional magnetization states.

Contribution

It introduces a model where spatially and temporally modulated potentials enable quantum spin pumping in a system with bond-alternation exchange interactions.

Findings

Quantum spin pumping occurs at certain fractional magnetization states.

Presence or absence of pumping explained by the system's quantum state.

Electric field induces a spin gap via bond-alternation exchange interactions.

Abstract

We study the quantum spin pumping of an antiferromagnetic spin-1/2 chain with competing exchange interactions. We show that spatially periodic potential modulated in space and time acts as a quantum spin pump. In our model system, an applied electric field causes a spin gap to its critical ground state by introducing bond-alternation exchange interactions. We study quantum spin pumping at different quantized magnetization states and also explain physically the presence and absence of quantum spin pumping at different fractionally quantized magnetization states.