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arXiv · 1505.03502

Mott-Hubbard transition and spin-liquid state on the pyrochlore lattice

Nyayabanta Swain·Rajarshi Tiwari·Pinaki Majumdar
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Abstract

The pyrochlore lattice involves corner sharing tetrahedra and the resulting geometric frustration is believed to suppress any antiferromagnetic order for Mott insulators on this structure. There are nevertheless short-range correlations which could be vital near the Mott-Hubbard insulator-metal transition. We use a static auxiliary-field-based Monte Carlo to study this problem in real space on reasonably large lattices. The method reduces to unrestricted Hartree-Fock at zero temperature but captures the key magnetic fluctuations at finite temperature. Our results reveal that increasing interaction drives the non magnetic (semi) metal to a 'spin disordered' metal with small local moments, at some critical coupling, and then, through a small pseudogap window, to a large moment, gapped, Mott insulating phase at a larger oupling. The spin disordered metal has a finite residual resistivity which grows with interaction strength, diverging at the upper coupling. We present the resistivity, optical conductivity, and density of states across the metal-insulator transition and for varying temperature. These results set the stage for the more complex cases of Mott transition in the pyrochlore iridates and molybdates.

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Nyayabanta Swain, Rajarshi Tiwari, Pinaki Majumdar. 2016-10-14. Mott-Hubbard transition and spin-liquid state on the pyrochlore lattice. https://doi.org/10.1103/physrevb.94.155119

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