2015/01/01 by Jianjun Ying, Ying, Jian-Jun, Lingyun Tang +13 · 1 citation
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Iron-based superconductors research #Materials Science (cond-mat.mtrl-sci) #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.1501.00330
openalex publication_date 2015/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Superconductivity of high critical temperature (Tc) superconductors is usually realized through chemical dopant or application of pressure in a similar way to induce charge carriers of either electrons or holes into their parent compounds. For chemical doping, superconductivity behaves asymmetrically with the maximum Tc often higher for optimal hole-doping than that of optimal electron-doping on the same parent compound. However, whether electron carriers could be in favour of higher Tc than holes in such high-Tc superconductors is unknown but attractive. Here we show that the application of pressure can drive KFe2As2 from hole- to electron-superconductivity after passing the previously reported V-shape or oscillation regime. The maximum Tc in the electron-dominated region is tripled to the initial value of 3.5 K or the average in the low-pressure hole-dominated region. The structural transition takes place from the tetragonal to collapsed tetragonal phase when the carrier characteristic is changed upon compression. Our results unambiguously offer a new route to further improve superconductivity with huge Tc enhancement for a compound through carrier switch. The strong electronic correlations in KFe2As2 are suggested to account for the unexpected enhancement of superconductivity in the collapsed tetragonal phase.