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V. P. Mineev

Publications and source records attributed to V. P. Mineev.

At least 37 records · Page 2Linked to original sources
arXiv2020

Dispersion-free optical activity in non-centrosymmetric metals

According to the Onsager principle a matrix of kinetic coefficients is symmetric in a system not violating time inversion symmetry. The antisymmetry is possible in systems with broken time inversion symmetry f.i. in systems in external magnetic field. An exception to this rule is presented here. It is shown that in a tetragonal metals with point group $C_{4v}$ not violating time inversion the conductivity tensor is antisymmetric. The corresponding optical properties are considered.

cond-mat.str-el↗
arXiv2020

Upper critical field in ferromagnetic metals with triplet pairing

The theory of triplet superconductivity in ferromagnetic metals based on electron-electron interaction by spin fluctuation exchange is developed. The equations for the upper critical field temperature dependence are derived. In contrast to the similar equations for the superconductivity in two band metals they contain the pairing amplitudes and the Fermi velocities depending on magnetic field. The critical field behaviour near the critical temperature and at T = 0 is established analytically.

cond-mat.supr-con↗
arXiv2018

Low-temperature resistance in metals without inversion Center

The well known quadratic low-temperature dependence of resistance in ordinary metals habitually serves as the criterium of applicability of the Landau Fermi liquid theory to the description of electron liquid in concrete material. Such a type of behavior is determined by momentum relaxation due to the electron-electron scattering.Here I consider this problem in the metals without inversion center. It is shown that the corresponding scattering time at temperatures much smaller than the spin-orbit coupling is practically temperature independent.

cond-mat.str-el↗
arXiv2018

Influence of Exchange Scattering on Superfluid He-3 states in Nematic Aerogel

The superfluid state in bulk liquid $^3$He is realized in the form of A or B phases. Uniaxially anisotropic aerogel (nafen) stabilizes transition from the normal to the polar superfluid state which on further cooling transitions to the axipolar orbital glass state (Phys. Rev. Lett. {\bf 115}, 165304 (2015)). This is the case in nafen aerogel preplated by several atomic layers of $^4$He. When pure liquid $^3$He fills the same nafen aerogel a solid-like layer of $^3$He atoms coats the aerogel structure. The polar state is not formed anymore and a phase transition occurs directly to the axipolar phase (Phys. Rev. Lett. {\bf 120}, 075301 (2018). The substitution of $^4$He by $^3$He atoms at the aerogel surface changes the potential and adds the exchange scattering of quasiparticles on the aerogel strands. A calculation shows that both of these effects can decrease the degree of anisotropy of scattering and suppress the polar phase formation. The derived anisotropy of the spin diffusion coefficient in globally anisotropic aerogel is determined by the same parameter which controls the polar state emergence which allows one to check the effect of anisotropy change for different types of covering.

cond-mat.other↗
arXiv2018

Theory of type-II superconductivity in ferromagnetic metals with triplet pairing

The superconducting state in uranium compounds UGe2, URhGe and UCoGe is formed at temperatures far below the Curie temperature pointing on nonconventional nature of superconductivity in these materials - namely the superconductivity with triplet pairing. The emergence of superconductivity is accompanied by the slight magnetization expulsion typical for the type-II superconductors. Following classic Abrikosov paper I develop the theory of type-II superconductivity in application to two-band ferromagnetic metal with equal spin triplet pairing.

cond-mat.supr-con↗
arXiv2017

Superconductivity in the Ferromagnet URhGe under uniaxial pressure

Uniaxial pressure applied in the b crystallographic direction perpendicular to spontaneous magnetization in heavy fermion ferromagnet URhGe strongly stimulates superconductivity in this compound. The phenomenological approach allows point out two mechanisms of superconducting temperature raising. They originates from stimulation by the uniaxial stress both intraband and interband amplitudes of triplet Cooper pairing. The phenomenon of reentrant superconductivity under magnetic field along b-axis is also strongly sensitive to the uniaxial stress in the same direction. The uniaxial stress accelerates suppression the Curie temperature by the transversal magnetic field. The emergence of the first order transition to the paramagnetic state occurs at much lower field than in the absence of uniaxial stress.

cond-mat.supr-con↗
arXiv2017

Superconductivity in Uranium Ferromagnets

The theoretical description and the survey of physical properties of superconducting states in the uranium ferromagnetic materials are presented. On the basis of microscopic theory is shown that the coupling between the electrons in these ferromagnetic metals by means of magnetization fluctuations gives rise the triplet pairing superconducting state and the general form of the order parameter dictated by the symmetry is established. The theory allows to explain some specific observations including peculiar phenomenon of reentrant superconductivity in URhGe in magnetic field perpendicular to the direction of spontaneous magnetization. In addition we describe several particular topics relating to uranium superconducting ferromagnets: (i) critical magnetic relaxation in dual localized-itinerant ferromagnets, (ii) phase transition to ferromagnetic state in Fermi liquid and UGe$_2$, (iii) superconducting ordering in ferromagnetic metals without inversion symmetry.

cond-mat.supr-con↗
arXiv2017

Phase diagram of UCoGe

The temperature-pressure phase diagram of ferromagnetic superconductor UCoGe includes four phase transitions. They are between the paramagnetic and the ferromagnetic states with the subsequent transition in the superconducting ferromagnetic state and between the normal and the superconducting states after which has to occur the transition to the superconducting ferromagnetic state. Here we have developed the Landau theory description of the phase diagram and established the specific ordering arising at each type of transition. The phase transitions to the ferromagnetic superconducting state are inevitably accompanied by the emergency of screening currents. The corresponding magnetostatics considerations allow to establish the significant difference between the transition from the ferromagnetic to the ferromagnetic superconducting state and the transition from the superconducting to the ferromagnetic superconducting state.

cond-mat.supr-con↗
arXiv2016

Antiferromagnetic order in CeCoIn5 oriented by spin-orbital coupling

An incommensurate spin density wave ($Q$ phase) confined inside the superconducting state at high basal plane magnetic field is an unique property of the heavy fermion metal CeCoIn$_5$. The neutron scattering experiments and the theoretical studies point out that this state come out from the soft mode condensation of magnetic resonance excitations. We show that the fixation of direction of antiferromagnetic modulations by a magnetic field reported by Gerber et al., Nat. Phys. {\bf 10}, 126 (2014) is explained by spin-orbit coupling. This result, obtained on the basis of quite general phenomenological arguments, is supported by the microscopic derivation of the $χ_{zz}$ susceptibility dependence on the mutual orientation of the basal plane magnetic field and the direction of modulation of spin polarization in a multi-band metal.

cond-mat.str-el↗
arXiv2016

NMR properties of the polar phase of superfluid He-3 in anisotropic aerogel under rotation

The polar phase of superfluid $^3$He is stable in "nematically ordered" densed aerogel. A rotating vessel with the polar superfluid can be filled either by an array of the single quantum vortices or by an array of the half-quantum vortices. It is shown that the inhomogeneous distribution of the spin part of the order parameter arising in an array of half-quantum vortices in strong enough magnetic field tilted to the average direction of aerogel strands leads to the appearance of a satellite in the NMR signal shifted in the negative direction with respect to the Larmor frequency. The satellite is absent in the case of an array of single quantum vortices what allows to distinguish these two configurations. The polar state in the anisotropic aerogel with lower density transforms at lower temperatures to the axipolar state. The array of half-quantum vortices created in the polar phase keeps its structure under transition to the axipolar state. The temperature dependence of the vortex-satellite NMR frequency is found to be slower below the transition temperature to the axipolar state.

cond-mat.supr-con↗
arXiv2015

URu2Si2: hidden order and amplitude of quantum oscillations

It is shown that the hidden ordered (HO) state in heavy fermionic metal URu2Si2 is either nonconventional charge density wave (CDW) or antiferroelectric (AFE) commensurate ordering. Similar to antiferromagnetic (AF) order an antiferroelectric order creates momentum dependence of conducting electrons $g$-factor. This even modest anisotropy along with the anisotropy of heavy cyclotron mass can produce multiple effect of so called zero-spin splitting in the amplitude of the de Haas - van Alphen and the Shubnikov - de Haas signals as function of direction of magnetic field.

cond-mat.str-el↗
arXiv2015

Reentrant superconductivity in URhGe

There is presented a phenomenological description of phase diagram of ferromagnet superconductor URhGe. In frame of the Landau phenomenological theory it was found that phase transition between anisotropic ferromagnetic and paramagnetic states under strong enough magnetic field perpendicular to direction of easy magnetization changes from the second to the first order type. It is shown that magnetic susceptibility corresponding to longitudinal magnetic fluctuations strongly increases in vicinity of the first order transition stimulating reentrance of superconducting state. The reentrant superconductivity observed near the first order transition line at temperatures about twice lower than the tricritical point temperature exists both in ferromagnet and paramagnet state. The critical temperature of transition to superconducting state falls down at intersection with line of ferromagnet-paramagnet phase transition.

cond-mat.supr-con↗
arXiv2014

Superconductivity in Uranium Compounds

On the basis of microscopic theory it is demonstrated how the coupling between the electrons by means of magnetization fluctuations in ferromagnetic metal with orthorhombic symmetry gives rise equal spin pairing superconducting state with general form of the order parameter dictated by symmetry. The strong upturn of the upper critical field along $b$-direction above 5 Tesla in UCoGe is explained by the increase of pairing interaction caused by the suppression of the Curie temperature by magnetic field parallel to b-axis. It is proposed that similar phenomenon at much higher field must take place also for the field directed along the magnetically hardest a-direction.

cond-mat.supr-con↗
arXiv2014

Superconducting phase transition of Sr2RuO4 in magnetic field

The superconducting state formed due to direct intra-orbital pairing in tetragonal multi-band superconductor Sr$_2$RuO$_4$ has different properties than the state formed due to intra-band pairing. In particular, the theory operating with direct intra-orbital pairing successfully explains the Kerr rotation of reflected light polarization observed several years ago. Here we apply intra-orbital approach to the problem of Ginzburg-Landau description of basal plane upper critical field in this material. It is shown that typical for two component superconducting state additional phase transition in the vortex state at $H<H_{c2}$ for all four crystallographic directions of magnetic field in the basal plane and the basal plane upper critical field anisotropy still are inevitable properties even in case of direct intra-orbital pairing.

cond-mat.supr-con↗
arXiv2014

Half-quantum vortices in polar phase of superfluid He-3

The magnetic dipole-dipole interaction does not prevent existence of half-quantum vortices in the polar phase of superfluid He-3 which can be stable in uniaxial anisotropic aerogel. Here we discus this exotic possibility. After developing a phenomenological theory of phase transition from the normal to polar superfluid state and then to axipolar superfluid state we calculate the NMR properties of such type superfluids at the rest or under rotation filled by an array either single quantum or half quantum vortices.

cond-mat.other↗
arXiv2014

Optical activity of noncentrosymmetric metals

We describe the phenomenon of optical activity of noncentrosymmetric metals in their normal and superconducting states. The found conductivity tensor contains the linear in wave vector off diagonal part responsible for the natural optical activity. Its value is expressed through the ratio of light frequency to the band splitting due to the spin-orbit interaction. The Kerr rotation of polarization of light reflected from the metal surface is calculated. In the additional file "Erratum" I've pointed out the sign error in arXiv:1001.2113 ( PRB v.81, 094525 (2010)) that leads to the wrong statement about the Kerr effect in light reflection from the surface of media without space parity.

cond-mat.supr-con↗
arXiv2013

Magnetostatics and optics of noncentrosymmetric metals

The current in noncentrosymmetric metals in normal and superconducting state is found in frame of linear response theory. In line with usual terms corresponding diamagnetic response, the Landau diamagnetism and the Pauli paramagnetism the general expression contains also the terms corresponding to spacial dispersion specific for a medium without space parity. This, so called, gyrotropic current is calculated in zero frequency case as well in infrared frequency region. The static gyrotropic current yields negligibly small correction to the London magnetostatics in a superconductor without inversion center. Whereas the high frequency response produces the natural-optical activity revealed f.e. in the Kerr effect. The magnitude of the Kerr angle in infrared frequency region is proved to be in reasonable correspondence with recently reported observations of the Kerr effect in the pseudogap phase in several different high Tc materials.

cond-mat.supr-con↗