CM In the literature: open

Why T-linear resistivity persists across the overdoped cuprate range

In plain words

A zero-temperature phase transition should affect a metal most strongly at a single value of the tuning parameter, yet in overdoped cuprates a part of the resistance stays linear in temperature over a wide range of doping.

Precise statement

In overdoped La2-xSrxCuO4, Tl2Ba2CuO6+d and Bi2Sr2CuO6+d with superconductivity suppressed by field, $\rho(T) = \rho_0 + A_1 T + A_2 T^{2}$ with $A_1$ nonzero from $p$* to near the end of the superconducting dome, decreasing with p and correlated with $T_c$ (Cooper et al., Science 2009). Determine whether this reflects an extended critical phase, spatial inhomogeneity mixing Fermi-liquid and critical regions, or a single critical point with a broad crossover. An answer is a model that reproduces $A_1(p)$, the $A_1\ \text{versus}\ T_c$ correlation, the magnetoresistance and the reduced Hall carrier density of the overdoped strange metal (Putzke et al., Nature Physics 2021).

What would settle it

Spatially resolved probes (NMR linewidths, scanning noise or nano-imaging) testing inhomogeneity on the same overdoped crystals, combined with a model fitted to $A_1(p)$, Hall and magnetoresistance data in two families.

Status in the literature

Magnetotransport across the overdoped range (Ayres et al., Nature 2021) was described by an incoherent T-linear channel coexisting with conventional carriers; the origin of that channel is unexplained.