Emergent Half Metal at Finite Temperatures in a Mott Insulator

Abstract

Sustaining exotic quantum mechanical phases at high temperatures is a long-standing goal of condensed matter physics. Among them, half-metals are spin-polarized conductors that are essential for realizing room-temperature spin current sources. However, typical half-metals are low-temperature phases whose spin polarization rapidly deteriorates with temperature increase. Here, we first show that a low-temperature insulator with an unequal charge gap for the two spin channels can arise from competing Mott and band insulating tendencies. We establish that thermal fluctuations can drive this insulator to a half-metal through a first-order phase transition by closing the charge gap for one spin channel. This half-metal has 100% spin polarization at the onset temperature of metallization. Further, varying the strength of electron repulsion can enhance the onset temperature while preserving spin polarization. We outline experimental scenarios for realizing this tunable finite temperature half-metal.

Published version

References in corpus (12)

• Half-metallic ferromagnets: From band structure to many-body effects
• Strong electronic correlations from Hund's coupling
• Tunable gauge potential for neutral and spinless particles in driven lattices
• Spin-orbit-entangled electronic phases in 4$d$ and 5$d$ transition-metal compounds
• Band alignment and charge transfer in complex oxide interfaces
• Quantum Monte Carlo Study of an Interaction-Driven Band Insulator to Metal Transition
• Momentum-dependent pseudogaps in the half-filled two-dimensional Hubbard model
• Electronic phase transitions in the half-filled ionic Hubbard model
• Testing the Monte Carlo - Mean Field approximation in the one-band Hubbard model
• Parallelized Traveling Cluster Approximation to Study Numerically Spin-Fermion Models on Large Lattices
• Magnetic interactions in the $S=1/2$ square-lattice antiferromagnets Ba${}_2$CuTeO${}_6$ and Ba${}_2$CuWO${}_6$: parent phases of a possible spin liquid
• Band-Insulator-Metal-Mott-Insulator transition in the half--filled $t-t^{\prime }$ ionic-Hubbard chain

Cited by in corpus (2)

• Layered Topological Antiferromagnetic Metal at Room Temperature -- YbMn${}_2$Ge${}_2$
• Charge transfer energy and band filling effects on two-hole Auger resonances in strongly correlated systems