Why Hall angle and resistivity follow different temperature laws
In plain words
In cuprates the resistance grows linearly with temperature while the Hall angle, the deflection of current by a magnetic field, behaves as if a second scattering rate grows as temperature squared.
Precise statement
In optimally doped cuprates $\rho_{xx} \sim T$ while cot(theta_H) = rho_xx/rho_xy ~ A + B T^2 over a wide range. Determine whether this requires two distinct relaxation rates (transport and Hall) or follows from a single anisotropic scattering rate on a Fermi surface with hot and cold regions. An answer is a model that reproduces both laws and their doping dependence with one parameter set.
What would settle it
Angle-dependent magnetoresistance mapping of the momentum-resolved scattering rate, fed into a Boltzmann or non-quasiparticle calculation that yields both $\rho_{xx}(T)$ and $\operatorname{cot}(\theta_{H})(T)$.
Related problems
- Special case of Microscopic origin of T-linear resistivity in strange metals