Search results for "ERC"
showing 10 items of 18589 documents
Field dependence of the vortex-core sizes in dirty two-band superconductors
2019
We study the structure of Abrikosov vortices in two-band superconductors for different external magnetic fields and different parameters of the bands. The vortex core size determined by the coherence lengths are found to have qualitatively different behaviour from that determined by the quasiparticle density of states spatial variation. These different vortex core length scales coincide near the upper critical field, while the discrepancy between them becomes quite significant at lower fields. Within the diffusive approximation we demonstrate several generic regimes in the field dependence of the vortex core sizes determined by the disparity of diffusion constants in the two bands.
Time-dependent quantum transport in nanosystems : a nonequilibrium Green's function approach
2016
A time-dependent extension to the Landauer–Büttiker approach to study transient quantum transport in arbitrary junctions composed of leads and conducting devices is developed. The nonequilibrium Green’s function approach is employed for describing the charge and heat transport dynamics. The importance of the developed method is that it provides a closed formula for the time-dependent density matrix in both electronic and phononic systems. In the electronic case the nonequilibrium conditions are due to a switch-on of a bias voltage in the leads or a perturbation in the junction whereas in the phononic case the central region of interest is coupled to reservoirs of di erent temperatures. In b…
Development of niobium-based superconducting junctions
2012
This thesis presents a review of publications which mainly focuses on the fabrication and performance of Nb-based normal metal-insulator-superconductor (NIS) tunnel junctions and superconductor-normal metal-superconductor (SNS) Josephson junctions at low temperatures. The Cu/AlOx-Al/Nb based NIS double tunnel junctions were successfully fabricated using conventional electron beam lithography combined with multi-angle thermal evaporation of metals in ultra high vacuum. The subgap characteristics of these junctions showed expected temperature dependence from 0.2 K to 5 K with a good thermometry sensitivity 0.2-0.3 mV/K. Signatures of small electronic cooling effects were observed near the Nb …
Chirality selective spin interactions mediated by the moving superconducting condensate
2018
We show that superconducting correlations in the presence of nonzero condensate velocity can mediate the peculiar interaction between localized spins that breaks the global inversion symmetry of magnetic moments. The proposed interaction mechanism is capable of removing fundamental degeneracies between topologically distinct magnetic textures. For the generic system of three magnetic impurities in the current-carrying superconductor, we find the energy term proportional to spin chirality. In realistic superconductor/ferromagnetic/superconductor setups we reveal significant energy differences between various magnetic textures with opposite chiralities. We calculate Josephson energies of junc…
Comparison of the Richardson and BCS models of superconductivity based on calculations of ground state energies
2017
Suprajohtavuuden Richardsonin ja BCS mallien vertailu perustilojen laskettujen energioiden perusteella. Suprajohtavuus on edelleen aktiivinen tutkimuksen alue, koska sen tarjoamista mahdollisuuksista huolimatta sitä ei vielä ymmärretä kokonaisvaltaisesti. Tässä pro gradu -tutkielmassa käyn läpi perusteet kahdelle suprajohtavuuden mallille, Richardsonin ja BCS malleille. BCS teoria on ensimmäinen ja käytetyin mikroskooppinen suprajohtavuuden teoria. Richardsonin malli on harvemmin käytetty malli, josta saadaan redusoidun BCS Hamiltonin operaattorin tarkat ominaistilat. Lasken molempien mallien perustilojen energiat sekä redusoidulle että täydelle BCS Hamiltonin operaattorille. Sama lasketaan…
Electron-phonon interaction in flat-band superconductivity
2017
Parhaiten tunnettu suprajohtavuuden syntymekanismi perustuu fononien välittämään vetovoimaan elektronien välillä. Tässä tutkielmassa tutkin fononien välittämää suprajohtavuutta systeemeissä, jossa elektronivyöt ovat tasomaisia. Tasovyöllä elektronien dispersio on erittäin heikko, jolloin tilatiheys on tavanomaista suurempi. Tämän takia suprajohtavuus tasovyöllä on tavanomaista voimakkaampi silloin kun elektronien välinen vetovoima on heikko. Eliashbergin teoria on elektroni–fononi-suprajohtavuuden teoria, joka ottaa luonnollisella tavalla fononien äärellisen nopeuden huomioon elektronien välisessä vuorovaikutuksessa. Pohjustuksena tasovyösuprajohtavuuteen perehdyn Eliashbergin teoriaan ensi…
Normal-Metal–Insulator–Superconductor Tunnel Junction With Atomic-Layer-Deposited Titanium Nitride as Superconductor
2015
A BRIEF ANATOMO-SURGICAL DISSECTION GUIDE TO HUMAN LOWER LIMB: RESULTS OF THE COLLABORATION BETWEEN THE UNIVERSITY OF PALERMO AND THE UNIVERSITY OF M…
2020
The aim of this Article is to show methods for dissection of the lower limb. In the summer 2017 a group of students at the University of Palermo that have already passed the exam of Human Anatomy took a 4 weeks dissection course at the University of Malta - School of Medicine. The students were provided with a dissection kit, video recording equipment and cameras for taking pictures. This paper presents the results of the dissection course and a small and simple guide to young students and medical doctors who want to learn the bases of lower limb dissection.
Importance of and need for intercultural education according to students: future teachers
2018
Abstract The aim of this article was to address the subject of intercultural education understood as a problem, which, in the process of educating students who will become teachers, should be taken into consideration in such a scope to make sure that the future teachers can support their pupils in the formation of desired attitudes and behaviours in their relations with individuals of different cultural, national and ethnic backgrounds. The first section deals with the importance of intercultural education in the context of the meaning of the following terms: multiculturalism, culture and education. It refers to selected scopes and interpretation of interculturalism and intercultural educa…
Forming ideal public-private partnerships for export practices : case exporting Resource Wisdom
2017
Vaikuttavien julkisen ja yksityisen sektorin vientikumppanuuksien muodostaminen : tapaustutkimus: Resurssiviisaus vientituotteeksi. Väestönkasvu ja urbanisaatio luovat kestävyyshaasteita, mutta myös mahdollistavat uuden liiketoiminnan ja kestävän kehityksen esiinmarssia. Tämä Pro gradu –tutkielma tarkastelee, miten kestävän aluekehityksen mallia, Resurssiviisautta, voidaan hyödyntää suomalaisten yritysten vientitukena julkisen ja yksityisen sektorin yhteistyöllä. Tutkimus keskittyy tämän yhteistyön muodostamiseen, sen johtamiseen ja ohjaamiseen kuin myös oikeaoppiseen yhteistyön hallinnointiin. Näitä aspekteja tarkastellaan etenkin kaupallisessa vientitarkoituksessa. Pro gradua varten haast…