Polarized monopole liquid: A Coulomb phase in a fluid of magnetic charges

SLOBINSKY, D.; PILI, L.; BORZI, R. A.

Physical Review B

AMER PHYSICAL SOC

Lugar: New York; Año: 2019 vol. 100

2469-9950

The forging of strong correlations on decreasing temperature can take place without the arousal of conventional order. If this happens, as in some geometrically frustrated magnets, disorder can be a phenomenon more interesting than order itself. A Coulomb phase, for example, has critical-like pair-spin correlations, leading to neutron scattering pinch points and emergent electromagnetism. Here we present a peculiar instance of disorder in an Ising pyrochlore lattice: the polarized monopole liquid (PML), a dense monopole fluid with pinch points in the magnetic charge-pair correlations. It is a phase of ?monopole matter? which, in principle, can be stabilized in real materials using a magnetic field and uniaxial stress along the [100] direction. To explain how the monopole correlations arise, we show that the PML is a Coulomb phase in which spin fluctuations cannot be assigned either to monopoles or to internal magnetic moments, but necessarily comprehend both degrees of freedom. We develop a simple but nontrivial method to Helmholtz decompose the spin field into a divergenceless and a divergenceful part in magnetic charge disordered pyrochlores that shows the appearance of pinch points associated with the divergenceful component in places where Bragg peaks are observed for the ?all-in/all-out? antiferromagnet.