Metal-insulator transition in Ca_{1-x}Li_xPd_3O_4

TL;DR

This study investigates the metal-insulator transition in Ca_{1-x}Li_xPd_3O_4 using charge transport measurements, revealing a simple one-band conduction mechanism and indicating localization-driven transition rather than excitonic insulator behavior.

Contribution

It provides experimental evidence that the metal-insulator transition in Ca_{1-x}Li_xPd_3O_4 is driven by localization effects, challenging previous theoretical predictions of excitonic insulator state.

Findings

Resistivity, Seebeck, and Hall coefficients are explained by a one-band model.

CaPd_3O_4 maintains finite carrier concentration down to 4.2 K.

Transition is driven by localization effects, not excitonic insulator formation.

Abstract

Metal-insulator transition in Ca_{1-x}Li_xPd_3O_4 has been studied through charge transport measurements. The resistivity, the Seebeck coefficient, and the Hall coefficient are consistently explained in terms of a simple one-band picture, where a hole with a moderately enhanced mass is itinerant three-dimensionally. Contrary to the theoretical prediction [Phys. Rev. B62, 13426 (2000)], CaPd_3O_4 is unlikely to be an excitonic insulator, and holds a finite carrier concentration down to 4.2 K. Thus the metal-insulator transition in this system is basically driven by localization effects.