Theory of the strange metal Sr <sub>3</sub> Ru <sub>2</sub> O <sub>7</sub>
Connie H. Mousatov, Erez Berg, Sean A. Hartnoll
Abstract
Significance The behavior of “strange metals” has eluded theoretical understanding for some time. It has remained unclear whether strange metals are fundamentally novel forms of matter or whether some unidentified variant of well-understood physics is at work. We show how the behavior of strontium ruthenate, a widely studied strange metal, follows in detail from well-established electronic properties. Specifically, strontium ruthenate contains “hot” electrons that are less quantum mechanical than the other “cold” electrons. A scattering process in which a cold electron becomes hot after colliding with a second cold electron is unusually strong, because the hot electrons are not subject to the Pauli exclusion principle. This fact is seen to underpin the strange metallicity of strontium ruthenate.