K. V. Samokhin

CePt3Si: An unconventional superconductor without inversion center

Most superconducting materials have an inversion center in their crystal lattices. One of few exceptions is the recently discovered heavy-fermion superconductor

Magnetic properties of superconductors with strong spin-orbit coupling

{\mathrm{CePt}}_{3}\mathrm{Si}

Model for superconductivity in ferromagnetic ZrZn2.

[E. Bauer et al., Phys. Rev. Lett. 92, 027003 (2004)]. In this paper, we analyze the implications of the lack of inversion symmetry for the superconducting pairing. We show that the order parameter is an odd function of momentum, and that there always are lines of zeros in the excitation energy gap for one-component order parameters, which seems to agree with the experimental data. The superconducting phase can be nonuniform, even without external magnetic field, due to the presence of unusual gradient terms in the Ginzburg-Landau free energy. Also, we performed ab initio electronic structure calculations for

Spin-orbit coupling in interacting quasi-one-dimensional electron systems

{\mathrm{CePt}}_{3}\mathrm{Si},

Paramagnetic properties of noncentrosymmetric superconductors: Application to CePt3Si

which showed that the spin-orbit coupling in this material is strong, and the degeneracy of the bands is lifted everywhere except along some high symmetry lines in the Brillouin zone.

De haas-van alphen effect in metals without an inversion center

We study the response of a superconductor with a strong spin-orbit coupling on an external magnetic field. The Ginzburg-Landau free energy functional is derived microscopically for a general crystal structure, both with and without an inversion center, and for an arbitrary symmetry of the superconducting order parameter. As a by-product, we obtain the general expressions for the intrinsic magnetic moment of the Cooper pairs. It is shown that the Ginzburg-Landau gradient energy in a superconductor lacking inversion symmetry has unusual structure. The general formalism is illustrated using as an example

Gap structure in noncentrosymmetric superconductors

{\mathrm{CePt}}_{3}\mathrm{Si}

Spin susceptibility of noncentrosymmetric superconductors

, which is the first known heavy-fermion superconductor without an inversion center.

Effects of interface spin-orbit coupling on tunneling between normal metal and chiral p-wave superconductor

We propose that superconductivity in the ferromagnetic state of ZrZn2 is stabilized by an exchange-type interaction between the magnetic moments of triplet-state Cooper pairs and the ferromagnetic magnetization density. This explains why superconductivity occurs in the ferromagnetic state only, and why it persists deep into the ferromagnetic state. The model of this article also yields a particular order parameter symmetry, which is a prediction that can be checked experimentally.

Spin–orbit coupling and semiclassical electron dynamics in noncentrosymmetric metals

We present a new model for the study of spin-orbit coupling in interacting quasi-one-dimensional systems and solve it exactly to find the spectral properties of such systems. We show that the combination of spin-orbit coupling and electron-electron interactions results in: the replacement of separate spin and charge excitations with two new kinds of bosonic mixed-spin-charge excitation, and a characteristic modification of the spectral function and single-particle density of states. Our results show how manipulation of the spin-orbit coupling, with external electric fields, can be used for the experimental determination of microscopic interaction parameters in quantum wires.