Violation of the isotropic mean free path approximation for overdoped ${\text{La}}_{2-x}{\text{Sr}}_x{\text{CuO}}_4$

Magnetotransport measurements on the overdoped cuprate ${\text{La}}_{1.7}{\text{Sr}}_{0.3}{\text{CuO}}_4$ are fitted using the Ong construction [Phys. Rev. B 43, 193 (1991)] and band parameters inferred from angle-resolved photoemission. Within a band picture, the low-temperature Hall data can only be fitted satisfactorily by invoking strong basal-plane anisotropy in the mean free path $\ell$. This violation of the isotropic-$\ell$ approximation supports a picture of dominant small-angle elastic scattering in cuprates due to out-of-plane substitutional disorder. We conjecture that both band anisotropy and anisotropy in the elastic-scattering channel strongly renormalize the Hall coefficient in ${\text{La}}_{2-x}{\text{Sr}}_x{\text{CuO}}_4$ across the entire overdoped regime.

Figure 1

(Color online) (a) $R_H\left(T\right)$ for ${\text{La}}_{1.7}{\text{Sr}}_{0.3}{\text{CuO}}_4$; the Drude value $\left(1/ne\right)$ is shown as a dashed line. (b) Fermi surface of ${\text{La}}_{1.7}{\text{Sr}}_{0.3}{\text{CuO}}_4$ (red dots) (Ref. 10) and tight-binding parametrization (solid light blue curve) (see Table ). The black dashed line represents the corresponding Fermi velocity whose peak value at $\phi =\pi /4$ is $v_F\left(\phi \right)=4\times {10}^5{\text{ms}}^{-1}$.

Figure 2

(Color online) (a) Section of 2D Fermi surface with pronounced negative curvature. The purple dashed (red solid) arrows indicate the direction and length of $\ell \left(\phi \right)$ $\left[k_F\left(\phi \right)\right]$, as explained in the text. (b) The polar plot of $\ell \left(\phi +\gamma \right)$. The tangential arrows indicate the circulation of each loop and the $-/+$ signs indicate the corresponding sign of ${\sigma }_{xy}$. The resultant ${\sigma }_{xy}$ is determined by the difference in the areas of the two counter-rotating loops $\left(\times 4\right)$ (Ref. 11).

Figure 3

(Color online) Measured [red circles (Ref. 6)] and band-derived [green diamonds (Table )] $R_H\left(300\right)$ values in overdoped LSCO compared to the Drude value $1/ne$ (dashed line).

Figure 4

(Color online)_ (a) ${\rho }_{ab}$, (b) $R_H$, and (c) $\Delta {\rho }_{ab}/{\rho }_{ab}$ data (red open circles) for LSCO30. The green solid (blue dotted) lines are the fits using the AV (sinusoidal) form for ${\Gamma }_0\left(\phi \right)$, respectively (see text for details). The error bars in (b) and (c) reflect scatter in the field sweeps.