Fully gapped d -wave superconductivity in CeCu 2 Si 2

• DOI: 10.1073/pnas.1720291115
• Publication Date: 2018-05-22T17:05:35Z
• Authors: Guiming Pang; Michael Smidman; Jinglei Zhang; Lin Jiao; Zongfa Weng; Emilian M. Nica; Ye Chen; Wenbing Jiang; Yongjun Zhang; Wu Xie; Hirale S. Jeevan; Hanoh Lee; Philipp Gegenwart; Frank Steglich; Qimiao Si; Huiqiu Yuan
• Keywords: London penetration depth; Cooper pair

Significance Identifying the gap structure of superconductors is vital for understanding underlying pairing mechanism Cooper pairs. The first heavy fermion superconductor to be discovered, CeCu 2 Si , was thought a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>d</mml:mi> </mml:math> -wave with nodes, until recent specific heat measurements provided evidence that fully open across Fermi surface. We propose resolution this puzzle from London penetration depth, which give further gapped superconductivity. analyze data using band-mixing model, leads superconducting gap. Our model accounts well depth and data, while reconciling nodeless sign-changing nature function.