Emergence of spin-active channels at a quantum Hall interface

Abstract

We study the ground state of a system with an interface between $\nu =4$ and $\nu =3$ in the quantum Hall regime. Far from the interface, for a range of interaction strengths, the $\nu =3$ region is fully polarized but $\nu =4$ region is locally a singlet. Upon varying the strength of the interactions and the width of the interface, the system chooses one of two distinct edge/interface phases. In phase A, stabilized for wide interfaces, spin is a good quantum number, and there are no gapless long-wavelength spin fluctuations. In phase B, stabilized for narrow interfaces, spin symmetry is spontaneously broken at the Hartree-Fock level. Going beyond Hartree-Fock, we argue that phase B is distinguished by the emergence of gapless long-wavelength spin excitations bound to the interface, which can, in principle, be detected by a measurement of the relaxation time $T_2$ in nuclear magnetic resonance.

arXiv comment9 pages 10 figures including supplemental material

References in corpus (9)

• Topological Insulators
• Sharp and Smooth Boundaries of Quantum Hall Liquids
• Quantum Ferromagnetism and Phase Transitions in Double-Layer Quantum Hall Systems
• Edge reconstruction in the $\nu =2/3$ fractional quantum Hall state
• Composite Edge States in the $\nu =2/3$ Fractional Quantum Hall Regime
• Skyrmions and edge spin excitations in quantum Hall droplets
• Spectroscopic Evidence for the Localization of Skyrmions near Nu=1 as T->0
• Spin Mode-Switching at the Edge of a Quantum Hall System
• Pump-probe nuclear spin relaxation study of the quantum Hall ferromagnet at filling factor nu = 2

Cited by in corpus (8)

• Emergence of Neutral Modes in Laughlin-like Fractional Quantum Hall Phases
• Collective excitations in chiral Stoner magnets
• Edge Reconstruction of a Time-Reversal Invariant Insulator: Compressible-Incompressible Stripes
• Dynamics of Quantum Hall Interfaces
• Edge Reconstruction and Emergent Neutral Modes in Integer and Fractional Quantum Hall Phases
• Magnon transmission across $\nu =1|-1|1$ mono-layer graphene junction as a probe of electronic structure
• Dc Electrical Current Generated by Upstream Neutral Modes
• Edge Reconstruction in a Quantum Spin Hall Insulator