SU(4) spin waves in the $\nu =\pm 1$ quantum Hall ferromagnet in graphene

Abstract

We study generalized spin waves in graphene under a strong magnetic field when the Landau-level filling factor is $\nu =\pm 1$. In this case, the ground state is a particular SU(4) quantum Hall ferromagnet, in which not only the physical spin is fully polarized but also the pseudo-spin associated with the valley degree of freedom. The nature of the ground state and the spin-valley polarization depend on explicit symmetry breaking terms that are also reflected in the generalised spin-wave spectrum. In addition to pure spin waves, one encounters valley-pseudo-spin waves as well as more exotic entanglement waves that have a mixed spin-valley character. Most saliently, the SU(4) symmetry-breaking terms do not only yield gaps in the spectra, but under certain circumstances, namely in the case of residual ground-state symmetries, render the originally quadratic (in the wave vector) spin-wave dispersion linear.

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Cited by in corpus (12)

• Thermodynamics of free and bound magnons in graphene
• Global phase diagram of charge neutral graphene in the quantum Hall regime for generic interactions
• Theory of broken symmetry quantum Hall states in the $N=1$ Landau level of Graphene
• Absence of heat flow in ν = 0 quantum Hall ferromagnet in bilayer graphene
• Phase diagram of the $\nu =2$ quantum Hall state in bilayer graphene
• Vanishing bulk heat flow in the nu=0 quantum Hall ferromagnet in monolayer graphene
• Fractional quantum Hall coexistence phases in higher Landau levels of graphene
• Magnetic and Lattice Ordered Fractional Quantum Hall Phases in Graphene
• Magnon transmission across $\nu =1|-1|1$ mono-layer graphene junction as a probe of electronic structure
• Anomalous Transport Gaps of Fractional Quantum Hall Phases in Graphene Landau Levels are Induced by Spin-Valley Entangled Ground States
• Magnon scattering and transduction in Coulomb-coupled quantum Hall ferromagnets
• Uniquely identifying quantum Hall phases in charge neutral graphene