Energy dependence of commensurate neutron scattering peak in doped two-leg ladder antiferromagnet Sr_{14-x}Ca_{x}Cu_{24}O_{41}

TL;DR

This paper investigates the energy dependence of the neutron scattering peak in doped two-leg ladder antiferromagnets, revealing a crossover from incommensurate to commensurate spin fluctuations and matching experimental observations.

Contribution

It introduces a fermion-spin approach to analyze spin responses, highlighting a crossover in magnetic behavior based on interchain coupling strength.

Findings

Crossover from incommensurate to commensurate spin fluctuations with increasing interchain coupling

Exponential decrease of nuclear spin-lattice relaxation rate at low temperatures

Quantitative agreement with experimental data on Sr_{14-x}Ca_{x}Cu_{24}O_{41}

Abstract

The dynamical spin response of doped two-leg ladder antiferromagnets is investigated based on the fermion-spin approach. Our calculations clearly demonstrate a crossover from the incommensurate antiferromagnetism in the weak interchain coupling regime to commensurate spin fluctuation in the strong interchain coupling regime. In particular, the nuclear spin-lattice relaxation rate extracted from the commensurate spin fluctuation decreases exponentially with decreasing temperatures. The behaviors of the spin dynamics in the strong coupling regime are quantitatively close to the experimental results of Sr_{14-x}Ca_{x}Cu_{24}O_{41}.