A novel chiral electron-hole (CEH) pairing mechanism is proposed to account for non-BCS superconductivity. In contrast to BCS Cooper pairs, CEH pairs exhibit a pronounced affinity to antiferromagnetism for superconductivity. The gap equations derived from this new microscopic mechanism are analyzed for both s- and d-wave superconductivity, revealing marked departures from the BCS theory. Unsurprisingly, CEH naturally describes superconductivity in strongly-correlated systems, necessitating an exceedingly large coupling parameter (\(\lambda>1\) for s-wave and \(\lambda>\pi/2\) for d-wave) to be efficacious. The new mechanism provides a better understanding of various non-BCS features, especially in cuprate and iron-based superconductors. In particular, CEH, through quantitative comparison with experimental data, shows promise in solving long-standing puzzles such as the unexpectedly large gap-to-critical-temperature ratio \(\Delta_0/T_c\), the lack of gap closure at \(T_c\), superconducting phase diagrams, and a non-zero heat-capacity-to-temperature ratio \(C/T\) at \(T=0\) (i.e., the “anomalous linear term”), along with its quadratic behavior near \(T=0\) for d-wave cuprates.
Conference (Mar. 6, 2024): Chiral Electron-Hole Condensation: A New Non-BCS Superconductivity Mechanism
In Session M16: Microscopic Theories of Superconductors I
Abstract:
A novel chiral electron-hole (CEH) pairing mechanism is proposed to account for non-BCS superconductivity. In contrast to BCS Cooper pairs, CEH pairs exhibit a pronounced affinity to antiferromagnetism for superconductivity. The gap equations derived from this new microscopic mechanism are analyzed for both s- and d-wave superconductivity, revealing marked departures from the BCS theory. Unsurprisingly, CEH naturally describes superconductivity in strongly-correlated systems, necessitating an exceedingly large coupling parameter (\(\lambda>1\) for s-wave and \(\lambda>\pi/2\) for d-wave) to be efficacious. The new mechanism provides a better understanding of various non-BCS features, especially in cuprate and iron-based superconductors. In particular, CEH, through quantitative comparison with experimental data, shows promise in solving long-standing puzzles such as the unexpectedly large gap-to-critical-temperature ratio \(\Delta_0/T_c\), the lack of gap closure at \(T_c\), superconducting phase diagrams, and a non-zero heat-capacity-to-temperature ratio \(C/T\) at \(T=0\) (i.e., the “anomalous linear term”), along with its quadratic behavior near \(T=0\) for d-wave cuprates.
Reference: arXiv:2310.10674