Exponential temperature dependence of the electrical resistivity of V3Si

Abstract

We report the results and interpretation of precision measurements of the electrical resistivity of V3Si in the temperature range Tc≤T≤77 K. Four samples of a wide range in residual resistance ratio (RRR) and with 15.1≤Tc≤16.8 K have been investigated. We find that the resistivity of all the samples is well described by a temperature dependence of the form ρ(T)=ρ0+bTn+dexp(-T0/T), where n falls within the range 1≤n≤2. The parameter d is sensitive to the RRR of the sample, whereas b and T0 are relatively insensitive. The characteristic temperature T0≈175 K is essentially independent of the choice of n within the stated range. A similar exponential term in ρ(T) of Nb3Sn with T0≈85 K has previously been identified by Woodard and Cody. Nothing that in both V3Si and Nb3Sn the value of T0 corresponds to the energy of [100] TA phonons near the zone boundary, we argue that the exponential term is due either to phonon-assisted interband scattering or intraband umklapp scattering. The reasons for the scattering effectiveness of this phonon will be discussed in light of recent band-structure calculations by Mattheiss and previous band models proposed to explain the anomalous normal-state properties of A-15 compounds. The nonexponential term in the resistivity is more difficult to characterize empirically and its origin is correspondingly more uncertain. We suggest it arises from intraband electron-electron scattering. The temperature dependence of the resistivity will be discussed with respect to anomalies observed in the low-temperature elastic constants, magnetic susceptibility, and specific heat of V3Si.