Thermodynamic Multipoles and Dissipative Conductivities in Metallic Systems
Abstract
Multipoles provide a systematic framework for describing the electronic structures of quantum materials from a symmetry perspective. Thermodynamic multipole moments in crystalline solids exhibit direct microscopic connections to certain allowed physical responses beyond symmetry; however, such relations have thus far been limited to dissipationless responses in equilibrium insulating systems. Here, this framework is extended at a heuristic level by focusing on the Fermi-surface contributions to thermodynamic multipole moments. These contributions establish direct relations to dissipative transport responses characteristic of metals, including charge and spin conductivities. A key consequence is that the conductivities exhibit extrema, typically maxima, at chemical potentials where the corresponding Fermi-surface contributions to the multipoles vanish, specifically, the electric quadrupole for charge conductivity and the magnetic octupole for spin conductivity. These findings uncover a previously overlooked aspect of thermodynamic multipole moments, opening a new perspective on dissipative transport in metallic systems.
Keywords
Cite
@article{arxiv.2603.29267,
title = {Thermodynamic Multipoles and Dissipative Conductivities in Metallic Systems},
author = {Takumi Sato and Satoru Hayami},
journal= {arXiv preprint arXiv:2603.29267},
year = {2026}
}