Why there is a difference between optimal doping for maximal and critical doping for highest in cuprate superconductors?

2012/10/23 by Zheyu Huang, Huaisong Zhao, Shiping Feng
Engineering · Physics and Astronomy · #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Superconductivity in MgB2 and Alloys #cond-mat.supr-con

paper · pdf · doi:10.1016/j.ssc.2013.04.024

published as Solid State Communications 165, 55 (2013) · 5 pages, 4 figures

arxiv created 2012/10/23 · openalex publication_date 2013/04/26 · arxiv updated 2013/05/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

A long-standing puzzle is why there is a difference between the optimal doping δ_optimal=0.15 for the maximal superconducting (SC) transition temperature Tc and the critical doping δ_critical=0.19 for the highest superfluid density ρ_s in cuprate superconductors? This puzzle is calling for an explanation. Within the kinetic energy driven SC mechanism, it is shown that except the quasiparticle coherence, ρ_s is dominated by the bare pair gap, while Tc is set by the effective pair gap. By calculation of the ratio of the effective and the bare pair gaps, it is shown that the coupling strength decreases with increasing doping. This doping dependence of the coupling strength induces a shift from the critical doping for the maximal value of the bare pair gap parameter to the optimal doping for the maximal value of the effective pair gap parameter, which leads to a difference between the optimal doping for the maximal Tc and the critical doping for the highest ρ_s.

Citations

• A gauge invariant dressed holon and spinon description of the normal state of underdoped cuprates
• Electronic structure of kinetic energy driven superconductors
• Two gaps make a high-temperature superconductor?
• Anomalous Peak in the Superconducting Condensate Density of Cuprate High-TcSuperconductors at a Unique Doping State