Testing the viability of the Landau-BCS paradigm: Is there physics beyond the "Standard Model" in overdoped cuprates?

Underdoped and optimally doped cuprates represent the epitome of doped Mott physics due to their proximity to the parent insulator, and exhibit not only superconductivity but other intertwined phases as well. However, starting from the opposite side of the phase diagram, it may be possible to describe the overdoped cuprates in terms of a BCS pairing state condensing from a Landau Fermi-liquid normal state. Numerous measurements on overdoped cuprates have recently challenged this notion and have been interpreted as evidence for physics beyond the Landau-BCS paradigm. It is therefore important to test the extent to which the d-wave BCS model can account for these experiments. A complication in pursuing this approach is the role of disorder, which acts in nonintuitive ways in a d-wave superconductor and can mask some of the clear experimental signatures expected in the clean limit. I will review key experiments, focusing on two of the most studied materials, LSCO and Tl-2201, and the challenges they present to the Landau-BCS approach. Starting with realistic parameterizations of ARPES band structure and reasonable assumptions about disorder, I will show that a wide range of low energy physical properties (e.g., absolute superfluid density, temperature dependence of superfluid density, THz conductivity, residual resistivity, thermal conductivity, Sommerfeld specific heat coefficient, and square-root-H Volovik effect) can be described with an exceptional level of internal consistency [1-3]. This work now includes spatially extended, ab-initio impurity potentials for the primary defects, and vertex corrections for the calculation of two-particle properties such as superfluid density and optical conductivity [4-6]. Recently, this work has been extended using a Migdal-Eliashberg approach to explain phenomena involving normal-state properties, including Homes’ law, where a new type of scaling has been proposed and tested against data for a wide range of superconductors [7].

[1] Lee-Hone et al, Phys. Rev. B 96, 024501 (2017)

[2] Lee-Hone et al, Phys. Rev. B 98, 054506 (2018)

[3] Lee-Hone et al., Phys. Rev. Res. 2, 013228 (2020)

[4] Özdemir et al, Phys. Rev. B 106,184510 (2022)

[5] Özdemir et al, Phys. Rev. Lett. 131, 049701 (2023)

[6] Broun et al, Phys. Rev. B 109, 174519 (2024)

[7] Broun et al, Phys. Rev. X 15, 041005 (2025)