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The metallic spinel Li2V2O4, an itinerant elecron system with geometrically frustrated pyrochlore lattice, was identified earlier as a transition metal oxide showing heavy fermion behavior.
In an attempt to explain inelastic scattering data for Li2V2O4, the dynamic spin susceptibility is calculated on the base of the realistic LDA band structure, which is supplemented first by the RPA treatment of strong local on-site electron interactions. These zero-temperature calculations suggest that the system is near to a magnetic instability. A role of geometrical frustration in forming this instability is discussed and a contribution of the "critical" spin fluctuations to the low-T specific heat coefficient is estimated. For finite temperatures, the approach is extended in the form of the self-consistent renormalization (SCR) theory including effects of spin fluctuation interaction. We show that a properly parametrized SCR theory is in agreement with the experimentally observed dynamic spin susceptibility measured in Li2V2O4 at low temperatures. |
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