Pseudogap phase of cuprate superconductors confined by Fermi surface topology

Abstract

The properties of cuprate high-temperature superconductors are largely shaped by competing phases whose nature is often a mystery. Chiefly among them is the pseudogap phase, which sets in at a doping $p^{\ast }$ that is material-dependent. What determines $p^{\ast }$ is currently an open question. Here we show that the pseudogap cannot open on an electron-like Fermi surface, and can only exist below the doping $p_{FS}$ at which the large Fermi surface goes from hole-like to electron-like, so that $p^{\ast }$ $\le$ $p_{FS}$. We derive this result from high-magnetic-field transport measurements in La${}_{1.6-x}$Nd${}_{0.4}$Sr${}_x$CuO${}_4$ under pressure, which reveal a large and unexpected shift of $p^{\ast }$ with pressure, driven by a corresponding shift in $p_{FS}$. This necessary condition for pseudogap formation, imposed by details of the Fermi surface, is a strong constraint for theories of the pseudogap phase. Our finding that $p^{\ast }$ can be tuned with a modest pressure opens a new route for experimental studies of the pseudogap.

15 pages, 5 figures, 7 supplemental figures