Fully Band Resolved Scattering Rate in MgB2 Revealed by Nonlinear Hall Effect and Magnetoresistance Measurements

摘要

We have measured the normal state temperature dependence of the Hall effectand magnetoresistance in epitaxial MgB2 thin films with variable disorderscharacterized by the residual resistance ratio RRR ranging from 4.0 to 33.3. Astrong nonlinearity of the Hall effect and magnetoresistance have been found inclean samples, and they decrease gradually with the increase of disorders ortemperature. By fitting the data to the theoretical model based on theBoltzmann equation and ab initio calculations for a four-band system, for thefirst time, we derived the scattering rates of these four bands at differenttemperatures and magnitude of disorders. Our method provides a unique way toderive these important parameters in multiband systems.