Magnetic field-induced soft mode in spin-gapped high-Tc superconductors

Abstract

We present an explanation of the dynamical in-gap spin mode in LSCO induced by an applied magnetic field H as recently observed by J. Chang et al. Our model consists of a phenomenological spin-only Hamiltonian, and the softening of the spin mode is caused by vortex pinning of dynamical stripe fluctuations which we model by a local ordering of the exchange interactions. The spin gap vanishes experimentally around H=7T which in our scenario corresponds to the field required for overlapping vortex regions.

4 pages, 3 figs

References in corpus (6)

• Two energy scales in the spin excitations of the high-T_c superconductor La${}_{2-x}$Sr${}_x$CuO${}_4$
• Magnetic-field-enhanced incommensurate magnetic order in the underdoped high-temperature superconductor YBa(2)Cu(3)O(6.45)
• Magnetic excitations in a bond-centered stripe phase: Spin waves far from the semi-classical limit
• Spin Waves in Striped Phases
• Field-induced soft-mode quantum phase transition in La${}_{1.855}$Sr${}_{0.145}$CuO${}_4$
• Magnetic field induced enhancement of spin-order peak intensity in La(1.875)Ba(0.125)CuO(4)