Nearly free electrons in the layered oxide superconductor Ag5Pb2O6

TL;DR

This study reports quantum oscillation measurements in Ag5Pb2O6, revealing a nearly-free electron Fermi surface and very light electron masses, establishing it as the first monovalent nearly-free electron superconductor at ambient pressure.

Contribution

It provides the first detailed electronic structure analysis of Ag5Pb2O6, demonstrating its nearly-free electron behavior and light effective masses.

Findings

Fermi surface consistent with nearly-free electrons

Electron masses approximately 1.2 times the electron mass

First example of a monovalent nearly-free electron superconductor at ambient pressure

Abstract

We present first measurements of quantum oscillations in the layered oxide superconductor Ag5Pb2O6. From a detailed angular and temperature dependent study of the dHvA effect we determine the electronic structure and demonstrate that the electron masses are very light, m^* is approximately equalt to 1.2 m_e. The Fermi surface we observe is essentially that expected of nearly-free electrons - establishing Ag5Pb2O6 as the first known example of a monovalent, nearly-free electron superconductor at ambient pressure.