Rotation-induced electric fields in metals and superconductors

Abstract

Recent attempts to design inertial sensors based on quantum-interference effects in high-Tc superconducting materials have led to a renewed interest in the origin of electric and magnetic fields in accelerated superconductors. In the case of a rotating superconductor, the formation of the London moment is well understood; however, there still exists some controversy concerning the direction and magnitude of the rotationally induced electric field. This situation is reminiscent of the old controversy concerning gravitationally induced electric fields in metals. In this paper we present a self-consistent theory of rotationally induced electric fields in both normal metals and superconductors. In the former case we treat normal carriers employing Thomas-Fermi theory; in the latter case we treat superelectrons using Ginzburg-Landau theory. In both cases we treat the lattice deformation with linear elastic theory. Self-consistent numerical solutions of these models show that the rotationally induced electric field in normal metals is given by E=-K(M/e)ω2r, where M is the mass of a lattice ion, e>0 is the magnitude of charge on an electron, ω is the angular velocity, r is the distance from the axis of rotation, and K is a positive-definite constant that depends on the lattice Lamé coefficients in a complicated way. This result is in qualitative agreement with previous analyses [Dessler et al., Phys. Rev. 168, 737 (1968); Herring, Phys. Rev. 171, 1361 (1968)]. The results we obtain for a rotating superconductor are markedly different. In this case the rotation-induced electric field is found to be E=K0(m*/e*)ω2r, where m* and e*>0 are the mass and magnitude of the charge of a Cooper pair, and K0≤1 is a material-dependent constant. K0 becomes progressively smaller than 1 with decreasing lattice stiffness.

Similar papers