Journal Article

Quantum critical scaling at the edge of Fermi liquid stability in a cuprate superconductor

Kirshenbaum, Kevin, Butch, Nicholas P, Jin, Kui, Greene, Richard L, Paglione, Johnpierre

2012

Overview

In the high-temperature cuprate superconductors, the pervasiveness of anomalous electronic transport properties suggests that violation of conventional Fermi liquid behavior is closely tied to superconductivity. In other classes of unconventional superconductors, atypical transport is well correlated with proximity to a quantum critical point, but the relative importance of quantum criticality in the cuprates remains uncertain. Here, we identify quantum critical scaling in the electron-doped cuprate material La2-xCexCuO4 with a line of quantum critical points that surrounds the superconducting phase as a function of magnetic field and charge doping. This zero-temperature phase boundary, which delineates a metallic Fermi liquid regime from an extended non-Fermi liquid ground state, closely follows the upper critical field of the overdoped superconducting phase and gives rise to an expanse of distinct non-Fermi liquid behavior at finite temperatures. Together with signatures of two distinct flavors of quantum fluctuations, these facts suggest that quantum criticality plays a significant role in shaping the anomalous properties of the cuprate phase diagram.

• Publisher: National Academy of Sciences,National Acad Sciences
• Subject: Algorithms / Chemical Phenomena / chemistry / Copper / Copper - chemistry / Critical points / Critical temperature / Cuprates / Doping / Electric Conductivity / electrical conductivity / Electrons / Fermi liquids / Ground state / High temperature / liquids / Magnetic Fields / Models, Chemical / Phase diagrams / Phase Transition / Physical Sciences / Power laws / Quantum physics / Quantum Theory / Superconductivity / Superconductors / Temperature / Thermodynamics / Transition Temperature