Large magnetic field-induced spectral weight enhancement of high-energy spin excitations in $L{a}_{1.88}S{r}_{0.12}Cu{O}_4$

Abstract

We report electronic Raman scattering experiments on a superconducting $\mathrm{L}{\mathrm{a}}_{1.88}\mathrm{S}{\mathrm{r}}_{0.12}\mathrm{Cu}{\mathrm{O}}_4$ single crystal in a magnetic field. At low temperatures, the spectral weight of the high-energy two-magnon peak increases linearly with field and is amplified by a factor of more than two at 14 T. The effect disappears at elevated temperatures and is not present in undoped $\mathrm{L}{\mathrm{a}}_2\mathrm{Cu}{\mathrm{O}}_4$. This observation is discussed in terms of an electronically inhomogeneous state in which the field enhances the volume fraction of a phase with local antiferromagnetic order at the expense of the superconducting phase.

to appear in PRL