Saturation of electrical resistivity

TL;DR

This paper reviews the phenomenon of resistivity saturation in metals, discussing experimental observations, classical and quantum theories, and cases where the traditional Ioffe-Regel condition is both satisfied and violated.

Contribution

It provides a comprehensive review of resistivity saturation, including recent theoretical developments that explain exceptions to the Ioffe-Regel rule in complex materials.

Findings

Resistivity saturation occurs when resistivity reaches a critical value.

Quantum derivation of the Ioffe-Regel condition under specific assumptions.

Violations of the Ioffe-Regel condition in high-Tc cuprates and fullerides.

Abstract

Resistivity saturation is observed in many metallic systems with a large resistivity, i.e., when the resistivity has reached a critical value, its further increase with temperature is substantially reduced. This typically happens when the apparent mean free path is comparable to the interatomic separations - the Ioffe-Regel condition. Recently, several exceptions to this rule have been found. Here, we review experimental results and early theories of resistivity saturation. We then describe more recent theoretical work, addressing cases both where the Ioffe-Regel condition is satisfied and where it is violated. In particular we show how the (semiclassical) Ioffe-Regel condition can be derived quantum-mechanically under certain assumptions about the system and why these assumptions are violated for high-Tc cuprates and alkali-doped fullerides.