Charge Transport in Synthetic Metals

TL;DR

This paper reviews charge transport phenomena in synthetic metals, highlighting the limitations of traditional theories, discussing Fermi liquid corrections, and presenting a model explaining linear resistivity in quasi-one-dimensional materials.

Contribution

It introduces an assisted-tunneling model with a quantum critical point to explain linear resistivity in certain low-dimensional materials.

Findings

Conventional quasiparticle and Boltzmann theories do not apply to synthetic metals.

Sr$_2$RuO$_4$ does not behave as a nearly-ferromagnetic Fermi liquid.

The assisted-tunneling model predicts resistivity linear in temperature or frequency.

Abstract

The phenomenology of charge transport in synthetic metals is reviewed. It is argued that the conventional quasiparticle picture and Boltzmann transport theory do not apply to these materials. The central ideas of Fermi liquid theory are reviewed, and the significant corrections produced by quasiparticle scattering from ferromagnetic spin fluctuations in liquid $^3$He are described. It is shown that Sr$_2$RuO$_4$ does not display the symptoms of a nearly-ferromagnetic Fermi liquid, so the source of its odd angular momentum pairing remains to be understood. The solution of an assisted-tunneling model of charge transport in quasi-one dimensional materials is described. This model has a quantum critical point and gives a resistivity that is linear in temperature or frequency, whichever is greater.