An enduring question in correlated systems concerns whether superconductivity is favored at a quantum critical point (QCP) characterized by a divergent quasiparticle effective mass. Despite such a scenario being widely postulated in high T(c) cuprates and invoked to explain non-Fermi liquid transport signatures, experimental evidence is lacking for a critical divergence under the superconducting dome. We use ultrastrong magnetic fields to measure quantum oscillations in underdoped YBa(2)Cu(3)O(6+x), revealing a dramatic doping-dependent upturn in quasiparticle effective mass at a critical metal-insulator transition beneath the superconducting dome. Given the location of this QCP under a plateau in T(c) in addition to a postulated QCP at optimal doping, we discuss the intriguing possibility of two intersecting superconducting subdomes, each centered at a critical Fermi surface instability.
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http://dx.doi.org/10.1073/pnas.0913711107 | DOI Listing |
Inorg Chem
January 2025
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Pressurized IrX (X = P and As) stands out as the sole -type superconductors among dozens of filled-skutterudites that are primarily characterized by -type charge carriers. The emergence of superconductivity is proposed to be intimately related to the inharmonic rattling phonons originating from the filled atoms. Here, we explore the impact of the size effect of the rattling atoms by substituting X with Sb, whose radius is 30 and 17% larger than those of P and As, respectively.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Department of Physics and Natural Science Research Institute, University of Seoul, Seoul 02504, Republic of Korea.
Bulk n-type SrTiO (STO) has long been known to possess a superconducting ground state at an exceptionally dilute carrier density. This has raised questions about the applicability of the BCS-Eliashberg paradigm with its underlying adiabatic assumption. However, recent experimental reports have set the pairing gap to the critical temperature (Tc) ratio at the BCS value for superconductivity in Nb-doped STO, even though the adiabaticity condition the BCS pairing requires is satisfied over the entire superconducting dome only by the lowest branch of optical phonons.
View Article and Find Full Text PDFNano Lett
January 2025
National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210023, P. R. China.
Transition metal oxide interfaces have garnered great attention due to their fascinating properties that are absent in their bulk counterparts. The high mobility and coexistence of superconductivity and magnetism at these interfaces remain compelling research topics. Here, we first report superconductivity in the 2DEG formed at the LaFeO/SrTiO interfaces, characterized by a superconducting transition temperature () of 333 mK and a superconducting layer thickness of 13.
View Article and Find Full Text PDFNat Commun
November 2024
High Field Magnet Laboratory (HFML-FELIX) and Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, Netherlands.
Commun Phys
November 2024
PSI Center for Neutron and Muon Sciences CNM, 5232 Villigen PSI, Switzerland.
Vacancies in solid-state physics are underexplored in materials with strong electron-electron correlations. Recent research on the Ir-Sb binary system revealed an extended buckled-honeycomb vacancy (BHV) order. Superconductivity arises by suppressing BHV ordering through high-pressure growth with excess Ir atoms or Rh substitution, yet the superconducting pairing nature remains unknown.
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