Thermodynamic Multipoles and Dissipative Conductivities in Metallic Systems

Takumi Sato; Satoru Hayami

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arXiv · 2603.29267

Thermodynamic Multipoles and Dissipative Conductivities in Metallic Systems

Takumi Sato·Satoru Hayami

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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.

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Takumi Sato, Satoru Hayami. 2026-03-31. Thermodynamic Multipoles and Dissipative Conductivities in Metallic Systems. https://arxiv.org/abs/2603.29267

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