Pseudogap phase of cuprate superconductors confined by Fermi surface topology.

Doiron-Leyraud, N; Cyr-Choinière, O; Badoux, S; Ataei, A; Collignon, C; Gourgout, A; Dufour-Beauséjour, S; Tafti, F F et al. · Nat Commun · 2017

basic_science · Level V

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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* that is material-dependent. What determines p* 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 <sub>FS</sub> at which the large Fermi surface goes from hole-like to electron-like, so that p* ≤ p <sub>FS</sub>. We derive this result from high-magnetic-field transport measurements in La<sub>1.6-x</sub> Nd<sub>0.4</sub>Sr <sub>x</sub> CuO<sub>4</sub> under pressure, which reveal a large and unexpected shift of p* with pressure, driven by a corresponding shift in p <sub>FS</sub>. 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* can be tuned with a modest pressure opens a new route for experimental studies of the pseudogap.