The Fermi surface and f-valence electron count of UPt3

TL;DR

This study uses de Haas-van Alphen and magnetoresistance data to analyze the Fermi surface of UPt3, challenging a localized 5f electron model and supporting a fully itinerant electron picture.

Contribution

It provides a comprehensive experimental and theoretical analysis favoring the fully itinerant model over the partially localized model for UPt3's electronic structure.

Findings

The fully itinerant model better predicts the Fermi surface features.

Identification of previously unrecognized extremal orbits.

Disconfirmation of the partially localized 5f electron model.

Abstract

Combining old and new de Haas-van Alphen (dHvA) and magnetoresistance data, we arrive at a detailed picture of the Fermi surface of the heavy fermion superconductor UPt3. Our work was partially motivated by a new proposal that two 5f valence electrons per formula unit in UPt3 are localized by correlation effects -- agreement with previous dHvA measurements of the Fermi surface was invoked in its support. Comprehensive comparison with our new observations shows that this 'partially localized' model fails to predict the existence of a major sheet of the Fermi surface, and is therefore less compatible with experiment than the originally proposed 'fully itinerant' model of the electronic structure of UPt3. In support of this conclusion, we offer a more complete analysis of the fully itinerant band structure calculation, where we find a number of previously unrecognized extremal orbits on the Fermi surface.