Naslov
Key role of incoherent carriers for superconductivity in overdoped cuprates

Autori
Čulo, Matija ; Duffy, Caitlin ; Ayres, Jake ; Berben, Maarten ; Hsu, Yu-Te ; Hinlopen, Roemer ; Bernáth, Bence ; Hussey, Nigel

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Skup
SCES 2020 - International Conference on Strongly Correlated Electron Systems

Mjesto i datum
Online, 27.09.2021. - 02.10.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
cuprates ; high-temperature superconductivity ; strange metal ; linear-temperature resistivity ; Fermi liquid ; Planckian dissipation ; incoherence ; high-field magnetoresistance ; quadrature scaling ; superfluid density ; coherent carrier density ; BCS theory

Sažetak
Mixed metallic copper oxides - cuprates - are one of the most studied materials in solid state physics due to their record high superconducting (SC) transition temperatures (at ambient pressure). This high-temperature SC state shows marked deviations from the conventional BCS theory and even after more than thirty years of intensive research is still poorly understood. Interestingly, the normal metallic, i.e. non-SC state of cuprates is also highly unconventional, as evidenced by pseudogap features in the underdoped part of the phase diagram and strange metal behavior in the overdoped part. The hallmark of the strange metal is the resistivity that above the SC transition follows an almost perfect linear temperature (T) dependence sometimes up to very high temperatures, even beyond the Mott-Ioffe- Regel limit. After the SC state has been destroyed, e.g. by a high magnetic field, T-linear resistivity continues down to the lowest temperatures, in sharp contrast with the standard Fermi liquid (FL) T2 dependence. T-linear resistivity is believed to be closely related to the so-called Planckian dissipation limit - the maximum dissipation in the system allowed by quantum mechanics - at which quasiparticles lose coherence and become incoherent. Our recent high- field magnetoresistance (MR) study of overdoped Tl2Ba2CuO6+δ and Bi2Sr2CuO6+δ showed that the strange metal phase in cuprates in fact comprises both types of charge carriers: incoherent carriers responsible for the strange metal T-linear resistivity and the observed quadrature scaling of MR and standard coherent quasiparticles responsible for the FL T2 resistivity and Hall response. Natural question then arises: which of the two types of carriers is responsible for high- temperature superconductivity? Here we show, with a minimal set of assumptions, that in overdoped Tl2Ba2CuO6+δ and La2-xSrxCuO4 the growth in superfluid density, as doping is decreased from the overdoped side, may be compensated by the loss in coherent carrier density and that their sum is approximately equal to the total carrier density. This correspondence leads us to postulate that superconductivity in overdoped cuprates, in contrast to any conventional BCS picture, emerges uniquely from incoherent, rather than coherent, carriers.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA