Strong suppression of weak (anti)localization in graphene

Low-field magnetoresistance is ubiquitous in low-dimensional metallic systems with high resistivity and well understood as arising due to quantum interference on self-intersecting diffusive trajectories. We have found that in graphene this weak-localization magnetoresistance is strongly suppressed and, in some cases, completely absent. This unexpected observation is attributed to mesoscopic corrugations of graphene sheets which cause a dephasing effect similar to that of a random magnetic field.Comment: improved presentation of the theory part after referees comments; important experimental info added (see "note added in proof"

Moscow Metropolis Labour Market Features: the Requirements of Employers and the Quality of Young Specialists

The subject-matter of the article is the study of the features of the youth labour market in such a specific region of Russia as the city of Moscow. The topic of the work is connected with the adaptation of training system for young specialists to the regional requirements of the employers of Moscow. The main hypothesis of the research suggests that the city of Moscow is an atypical region of Russia and it makes no sense to apply the standard criteria and methodological approaches, which are typical to our country, to its labour market. As the research method, the authors have used a sample survey of the key Moscow employers and the respondents aged from 14 to 30 years. On the basis of the data of the sociological survey conducted by the authors, it was succeeded to identify the following features of the region in question: a relatively low level of the youth unemployment for Russia; the employers’ focus on such target signs of personnel as good communication skills, learning ability, professional knowledge and competences. The Moscow employers pay insufficient attention to such characteristics of young specialists as foreign language and computer skills, and a diploma of a prestigious education institution. The principal barriers that cause dificulties to the employment of young specialists in Moscow are: their overestimated salary expectations, poor professional training level and disinclination for work in principle. As a result of the survey, some practical proposals were formulated. Their application area is differentiated in two ways: focused on the young people’s behavior at the learning stage and focused on the improvement of the practical component of the activity of the vocational education institutions. The authors have come to the conclusions on the expediency of a deep focus of education institutions on the applied nature of training specialists, a need for attracting practitioners to teaching special disciplines, a need for developing the future specialists’ ability to present themselves and their work results in the professional environment (self-presentation), and an objective assessment of their real employment opportunities.The authors of the article hereby express their gratitude to the Department of Labour and Social Protection of the Population of Moscow for its assistance in conducting the research of the problems of youth employment in the city of Moscow. The article is published with support of the RSF grant, Project “Fluctuating Unemployment in the Russian Federation: the Status and the Ways of Reduction” № 16–18–1014

Magnon influence on the superconducting DOS in FI/S bilayers

Heterostuctures superconductor/ferromagnetic insulator (FI/S) are paradigmic systems for studying mutual influence of superconductivity and magnetism via proximity effects. In particular, spin-split superconductivity is realized in such structures. Recent experiments and theories demonstrate a rich variety of transport phenomena occurring in devices based on such heterostructures that suggest direct applications in thermoelectricity, low-dissipative spintronics, radiation detection and sensing. In this work we investigate the influence of the electron-magnon interaction at the superconductor/ferromagnetic insulator interface on the spin-split superconductivity. It is predicted that due to the magnon-mediated electron spin-flip processes the spin-split quasiparticle branches are partially mixed and reconstructed, and the BCS-like spin-split shape of the superconducting DOS, which is typical for superconductors in the effective exchange field, is strongly modified. An odd-frequency superconducting order parameter admixture to the leading singlet order parameter is also found. These findings expand the physical picture of spin-split superconductivity beyond the mean-field description of the ferromagnet exchange field

Renormalization of antiferromagnetic magnons by superconducting condensate and quasiparticles

The ability to modify and tune the spin-wave dispersion is one of the most important requirements for engineering of magnonic networks. In this study we demonstrate the promise of synthetic thin-film hybrids composed of an antiferromagnetic insulator (AF) and a normal (N) or superconducting (S) metal for tuning and modifying the spin-wave dispersion in antiferromagnetic insulators. The key ingredient is the uncompensated magnetic moment at the AF/S(N) interface, which induces an effective exchange field in the adjacent metal via the interface exchange interaction. The exchange field spin polarizes quasiparticles in the metal and induces spinful triplet Cooper pairs screening the magnon. The quasiparticle and Cooper pair polarization renormalizes the magnon dispersion. The renormalization results in the splitting of the otherwise degenerate AF magnon modes with no need to apply a magnetic field. It is also proposed that measurements of the renormalized dispersion relations can provide the amplitude of the effective exchange field induced by the AF in the adjacent metal

Anomalous phase shift in a Josephson junction via an antiferromagnetic interlayer

The anomalous ground state phase shift in S/AF/S Josephson junctions in the presence of the Rashba SO-coupling is predicted and numerically investigated. It is found to be a consequence of the uncompensated magnetic moment at the S/AF interfaces. The anomalous phase shift exhibits a strong dependence on the value of the SO-coupling and the sublattice magnetization with the simultaneous existence of stable and metastable branches. It depends strongly on the orientation of the Neel vector with respect to the S/AF interfaces via the dependence on the orientation of the interface uncompensated magnetic moment, what opens a way to control the Neel vector by supercurrent in Josephson systems.Comment: published versio

Особливості вогнепальних пошкоджень бавовняного одягу в разі пострілу впритул в імітатор людського торса з пістолета «Форт-12РМ»

This Article Purpose is to determine specifics of damage to cotton jer-sey, arising from a point-blank shot from a nickel-plated “Fort-12RM” pistol, equipped with .45 Rubber cartridges into  dressed simulator of a human torso made of ballistic gel. For achieving this goal, 12 human torso simulators were made, dressed in cotton T-shirts, with the subsequent firing of shots using a nick-el-plated “Fort-12RM” pistol equipped with .45 Rubber cartridges. The shots were fired from a distance, closely followed by examination of damage to cloth-ing using photographic and microscopic research methods. Obtained data and their comparison with the previously obtained research results when the shots were fired at the clothing samples, fixed in the frame made it possible to identify important differences and for the first time describe the phenomenon of internal muzzle imprint mark and volumetric muzzle imprint mark; while describing the internal muzzle imprint mark, specific deposition of additional factors of the shot (namely, soot), reminiscent of a candle flame was found. In addition, a double marker phenomenon was observed around the input gunshot injury on the inves-tigated human torso simulator. Most of  additional factors of the shot (in form of soot and dust particles of unburned gunpowder) were determined in wound channel. While carrying out the contact-diffusion method of research, small particles of nickel were determined around input fire damage to the simulator. The revealed differences require revision of the classical method of experimental shooting, while test samples of clothing are fixed in a frame or fixed in a similar way. An important stage in research formulation is to recreate the conditions as close as possible to real ones. The search for the most appropriate, efficient and simple method for carrying out such experiments is promising for ballisticsЗброя нелетальної дії набуває дедалі більшого поширення як у військових формуваннях, так і поміж цивільного населення, адже такий вид зброї створено не для знищення супротивника, а лише для його нейтралізації з мінімальною шкодою для здоров’я. Проте, це не заважає злочинцям застосовувати цей вид зброї для вчинення кримінальних дій. Особливо це стосується вогнепальної зброї нелетальної дії (здебільшого травматичних пістолетів).  Мета роботи — визначити особливості пошкоджень бавовняного трикотажу, які виникають у разі пострілу впритул з нікельованого пістолета «Форт-12РМ», спорядженого патронами .45 Rubber, в одягнутий імітатор людського торса, виготовлений із балістичного гелю. Для досягнення поставленої мети 12 імітаторів людського торса вдягли в бавовняні футболки, по ним виконували постріли впритул з ніке-льованого пістолета «Форт-12РМ», спорядженого патронами .45 Rubber, із подальшим дослідженням пошкоджень одягу фотографічним і мікроскопічним методами. Порівняння здобутих результатів з більш ранніми, коли постріли виконували у зразки одягу, закріплені в рамці, дали змогу вперше описати феномен внутрішньої штанцмарки й об’ємної штанцмарки: під час опису внутрішньої штанцмарки виявлено специфічне відкладан-ня додаткових факторів пострілу (а саме — кіптяви), що нагадує полум’я свічки. Окрім того, спостерігали феномен подвійної штанцмарки навколо вхідного вогнепального пошкодження на досліджуваному імітаторі людського торса. Більшість додаткових факторів пострілу (у вигляді кіптяви та порошинок незгорілого пороху) виявлено в рановому каналі. Під час проведення контактно-дифузійного методу дослідження навколо вхідного вог-непального пошкодження імітатора спостерігали дрібні частинки нікелю. Виявлені відмінності вимагають перегляду класичної методики проведення експериментальних відстрілів, коли досліджувані зразки одягу закріплюють у рамці або фіксують у схожий спосіб. Важливим етапом постановки дослідження є відтворення умов, максимально наближених до реальних. Пошук найбільш доречного, ефективного та простого методу для здійснення таких експериментів є перспективним для балістики

Proximity-driven source of highly spin-polarized ac current on the basis of superconductor/weak ferromagnet/superconductor voltage-biased Josephson junction

We theoretically investigate an opportunity to implement a source of highly spin-polarized ac current on the basis of superconductor/weak ferromagnet/superconductor (SFS) voltage-biased junction in the regime of essential proximity effect and calculate the current flowing through the probe electrode tunnel coupled to the ferromagnetic interlayer region. It is shown that while the polarization of the dc current component is generally small in case of weak exchange field of the ferromagnet, there is an ac component of the current in the system. This ac current is highly spin-polarized and entirely originated from the non-equilibrium proximity effect in the interlayer. The frequency of the current is controlled by the voltage applied to SFS junction. We discuss a possibility to obtain a source of coherent ac currents with a certain phase shift between them by tunnel coupling two probe electrodes at different locations of the interlayer region.Comment: 8 pages, 5 figure

Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

Recent achievements in studies of the effects of ICRF (Ion Cyclotron Range of Frequencies) power on the SOL (Scrape-Off Layer) and PWI (Plasma WallInteractions) in ASDEX Upgrade (AUG),Alcator CMod,and JETIL Ware reviewed. Capabilities to diagnose and model the effect of DCbiasingand associated impurity production atactive antenna sandon magnetic field connections to antennas are described. The experiments show that ICRFnearfields can lead not only to E×B convection, but also to modifications of the SOL density,which for Alcator CMod are limited to anarrow regionne arantenna. On the other hand, the SOL density distribution along with impurity sources can be tail or edusing localg as injection in AUG and JET-ILW with a positive effect on reduction of impurity sources.The technique of RFimage current cancellation atantennalimiters was successfully applied in AUG using the 3-strap AUG antenna and extended to the 4-strap Alcator C-Mod field-aligned antenna.MultipleobservationsconfirmedthereductionoftheimpactofICRFontheSOLandontotalimpuritypro-ductionwhentheratioofthepowerofthecentralstrapstothetotalantennapowerisintherange0.6<Pcen/Ptotal<0.8.Near-fieldcalculationsindicatethatthisfairlyrobusttechniquecanbeappliedtotheITERICRFantenna,enablingthemodeofoperationwithreducedPWI.Onthecontrary,fortheA2antennainJET-ILWthetechniqueishinderedbyRFsheathsexcitedattheantennaseptum.Thus,inordertoreducetheeffectofICRFpoweronPWIinafuturefusionreactor,theantennadesignhastobeoptimizedalongwithdesignofplasma-facingcomponents.https://doi.org/10.1016/j.nme.2018.11.017Received26July2018;Accepted22November2018⁎Correspondingauthor.E-mailaddress:[email protected](V.Bobkov).1Seetheappendixof"A.Kallenbachetal.,2017Nucl.Fusion57102015”.2Seetheauthorlistof"H.Meyeretal.,2017Nucl.Fusion57102014”.3Seetheauthorlistof"X.Litaudonetal.,2017Nucl.Fusion57102001”.Nuclear Materials and Energy 18 (2019) 131–140Available online 20 December 20182352-1791/ © 2018 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).TEURATOM 633053US DoE, Office of Science,Office of Fusion Energy Sciences,User Facility Alcator C-Mod DE-FC02-99ER54512, DE-SC0010720, DE-AC05-00OR227

Electronic structure of d-wave superconducting quantum wires

We present analytical and numerical results for the electronic spectra of wires of a d-wave superconductor on a square lattice. The spectra of Andreev and other quasiparticle states, as well as the spatial and particle-hole structures of their wave functions, depend on interference effects caused by the presence of the surfaces and are qualitatively different for half-filled wires with even or odd number of chains. For half-filled wires with an odd number of chains N at (110) orientation, spectra consist of N doubly degenerate branches. By contrast, for even N wires, these levels are split, and all quasiparticle states, even the ones lying above the maximal gap, have the characteristic properties of Andreev bound states. These Andreev states above the gap can be interpreted as a consequence of an infinite sequence of Andreev reflections experienced by quasiparticles along their trajectories bounded by the surfaces of the wire. Our microscopic results for the local density of states display atomic-scale Friedel oscillations due to the presence of the surfaces, which should be observable by scanning tunneling microscopy. For narrow wires the self-consistent treatment of the order parameter is found to play a crucial role. In particular, we find that for small wire widths the finite geometry may drive strong fluctuations or even stablilize exotic quasi-1D pair states with spin triplet character.Comment: 21 pages, 20 figures. Slightly modified version as published in PR