Resistivity and Hall effect of LiFeAs: Evidence for electron-electron scattering

LiFeAs is unique among the broad family of FeAs-based superconductors, because it is superconducting with a rather large $T_c\simeq 18$ K under ambient conditions although it is a stoichiometric compound. We studied the electrical transport on a high-quality single crystal. The resistivity shows quadratic temperature dependence at low temperature, giving evidence for strong electron-electron scattering and a tendency toward saturation around room temperature. The Hall constant is negative and changes with temperature, which most probably arises from a Van Hove singularity close to the Fermi energy in one of the holelike bands. Using band structure calculations based on angular resolved photoemission spectra we are able to reproduce all the basic features of both the resistivity as well as the Hall effect data.

Figure 1

In-plane resistivity for different magnetic fields applied either (a) parallel or (b) perpendicular to the $c$ axis. Panel (b) displays two data sets: one (lines) with the field parallel and another (symbols) with the field perpendicular to the current. (c) Phase boundaries for both field directions together with linear fits (dashed lines). The transition temperatures are defined as $T_c=(T_{90}+T_{10})/2$ and the transition widths $\Delta =T_{90}-T_{10}$ are displayed as horizontal bars.

Figure 2

In-plane resistivity of LiFeAs as a function of temperature. The inset displays the low-$T$ zero-field resistivity and $\rho \left(T\right)$ measured in 15 T together with a quadratic fit (line) in a representation $\rho$ vs $T^2$ (see text).

Figure 3

Hall coefficient of LiFeAs as a function of temperature (symbols). The dashed line shows the expected Hall coefficient derived from a band-structure calculation based on ARPES data (see text).