Influence of carbon on intraband scattering in Mg(B1-xCx)2

TL;DR

This study investigates how carbon substitution in Mg(B1-xCx)2 affects intraband scattering, revealing increased electron-impurity scattering primarily in the pi band, with systematic changes in Hall coefficient behavior.

Contribution

It provides experimental data on the Hall coefficient and transport properties of carbon-doped MgB2, highlighting the role of impurity scattering in normal-state transport.

Findings

Hall coefficient varies systematically at low temperatures

Carbon substitution enhances scattering rates in the pi band

Transport properties are dominated by impurity scattering, not charge carrier concentration

Abstract

We report data on the Hall coefficient (RH) of the carbon substituted Mg(B1-xCx)2 single crystals with x in the range from 0 to 0.1. The temperature dependences of RH obtained for the substituted crystals differ systematically at low temperatures, but all of them converge to the value of 1.8 x 10^-10 m^3/C at room temperature. The RH(T) data together with results of the thermoelectric power and electrical resistivity measurements are interpreted within a quasi-classical transport approach, where the presence of four different conducting sheets is considered. The main influence of the carbon substitution on the transport properties in the normal state is associated with enhanced scattering rates, rather than modified concentration of charge carriers. Presumably the carbon substitution increases the electron-impurity scattering mainly in the pi band.