2015/12/22 by J. P. Sun, K. Matsuura, G. Z. Ye +12 · 1 citation
Physics and Astronomy · #cond-mat.supr-con #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1038/ncomms12146
published as Nat. Commun. 7, 12146 (2016) · 15 pages, 4 figures
arxiv created 2015/12/22 · arxiv updated 2016/07/20
The coexistence and competition between superconductivity and electronic orders, such as spin or charge density waves, have been a central issue in high transition-temperature (T\rm c) superconductors. Unlike other iron-based superconductors, FeSe exhibits nematic ordering without magnetism whose relationship with its superconductivity remains unclear. More importantly, a pressure-induced fourfold increase of T\rm c has been reported, which poses a profound mystery. Here we report high-pressure magnetotransport measurements in FeSe up to ∼9 GPa, which uncover a hidden magnetic dome superseding the nematic order. Above ∼6 GPa the sudden enhancement of superconductivity (T\rm c≤38.3 K) accompanies a suppression of magnetic order, demonstrating their competing nature with very similar energy scales. Above the magnetic dome we find anomalous transport properties suggesting a possible pseudogap formation, whereas linear-in-temperature resistivity is observed above the high-T\rm c phase. The obtained phase diagram highlights unique features among iron-based superconductors, but bears some resemblance to that of high-T\rm c cuprates.