Hidden magnetism at the pseudogap critical point of a cuprate superconductor

• DOI: 10.1038/s41567-020-0950-5
• Publication Date: 2020-07-06T16:03:42Z
• Authors: Mehdi Frachet; Igor Vinograd; Rui Zhou; Siham Benhabib; Shangfei Wu; Hadrien Mayaffre; Steffen Krämer; Sanath K. Ramakri...; Arneil P. Reyes; Jérôme Debray; Tohru Kurosawa; Naoki Momono; Migaku Oda; Seiki Komiya; Shimpei Ono; Masafumi Horio; Johan Chang; Cyril Proust; David LeBoeuf; Marc-Henri Julien
• Keywords: Strongly Correlated Electrons (cond-mat.str-el); 530 Physics; Condensed Matter - Superconductivity; 500; General Physics and Astronomy; FOS: Physical sciences; 10192 Physics Institute; 530; 01 natural sciences; 3100 General Physics and Astronomy; [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con]; Superconductivity (cond-mat.supr-con); Condensed Matter - Strongly Correlated Electrons; 0103 physical sciences

26 pages, supplementary info included<br/>The mysterious pseudogap phase of cuprate superconductors ends at a critical hole doping level p* but the nature of the ground state below p* is still debated. Here, we show that the genuine nature of the magnetic ground state in La2-xSrxCuO4 is hidden by competing effects from superconductivity: applying intense magnetic fields to quench superconductivity, we uncover the presence of glassy antiferromagnetic order up to the pseudogap boundary p* ~ 0.19, and not above. There is thus a quantum phase transition at p*, which is likely to underlie highfield observations of a fundamental change in electronic properties across p*. Furthermore, the continuous presence of quasi-static moments from the insulator up to p* suggests that the physics of the doped Mott insulator is relevant through the entire pseudogap regime and might be more fundamentally driving the transition at p* than just spin or charge ordering.<br/>