Magnetic field induced incommensurate resonance in cuprate superconductors

TL;DR

This paper investigates how an external magnetic field affects the spin response in cuprate superconductors, revealing a transition from commensurate to incommensurate resonance and modifications in magnetic scattering patterns.

Contribution

It introduces a theoretical framework showing magnetic field-induced incommensurate resonance in cuprate superconductors, highlighting changes in magnetic scattering and dispersion.

Findings

Magnetic scattering is significantly altered by modest magnetic fields.

Incommensurate magnetic resonance can be induced by applying a strong magnetic field.

The spin excitation dispersion exhibits an hourglass-like shape that breaks down at low energies.

Abstract

The influence of a uniform external magnetic field on the dynamical spin response of cuprate superconductors in the superconducting state is studied based on the kinetic energy driven superconducting mechanism. It is shown that the magnetic scattering around low and intermediate energies is dramatically changed with a modest external magnetic field. With increasing the external magnetic field, although the incommensurate magnetic scattering from both low and high energies is rather robust, the commensurate magnetic resonance scattering peak is broadened. The part of the spin excitation dispersion seems to be an hourglass-like dispersion, which breaks down at the heavily low energy regime. The theory also predicts that the commensurate resonance scattering at zero external magnetic field is induced into the incommensurate resonance scattering by applying an external magnetic field large enough.