Mott transition and anomalous resistive state in the pyrochlore molybdates

Abstract

The rare-earth based pyrochlore molybdates involve orbitally degenerate electrons Hund's coupled to local moments. The large Hund's coupling promotes ferromagnetism, the superexchange between the local moments prefers antiferromagnetism, and Hubbard repulsion tries to open a Mott gap. The phase competition is tuned by the rare-earth ionic radius, decreasing which leads to change from a ferromagnetic metal to a spin disordered highly resistive ground state, and ultimately an 'Anderson-Mott' insulator. We attempt a quantitative theory of the molybdates by studying their minimal model on a pyrochlore geometry, using a static auxiliary field based Monte Carlo. We establish a thermal phase diagram that closely corresponds to the experiments, predict the hitherto unexplored orbital correlations, quantify and explain the origin of the anomalous resistivity, and present dynamical properties across the metal-insulator transition.

6 pages with 5 figs

References in corpus (8)

• Nature of the superconductor-insulator transition in disordered superconductors
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Cited by in corpus (2)

• Strain induced superconductor-insulator transition on Lieb lattice
• Transport and spectroscopic signatures of a disorder-stabilized metal in two-dimensional frustrated Mott insulators