Metallicity without quasi-particles in room-temperature strontium titanate

Abstract

Correlated matter: When metals go bad An expected metallic behavior that defies existing theory is observed by researchers in France. Xiao Lin from the Laboratoire Physique et Etude de Matériaux and co-workers show that room temperature strontium titanate behaves like a so-called ‘bad’ metal. Particles with an electric charge can flow through a metal with little resistance. But this resistivity increases with particle density. In conventional metals, this increase eventually stops at what is known as the Mott-Ioffe-Regel limit. Bad or strange metals, however, defy this rule and the resistivity continues to increase. This effect is thought to arise when the when the electrons work collectively, creating quasi-particles. Lin and colleagues show that this bad metal behavior can occur even in a material without quasi-particles. Instead, they argue the metallicity is caused by so-called Landauer transmission between individual dopants.