Search results for "orbit"
showing 10 items of 1104 documents
Exotic Spin-Orbital Physics in Hybrid Oxides
2016
We compare the effective spin-orbital super\-exchange triggered by magnetic $3d$ impurities with $d^3$ and $d^2$ configurations and either no orbital degree of freedom (orbital dilution) or hole replacing a doublon (charge dilution) in a $4d^4$ Mott insulator with $S=1$ spins. Impurities causing orbital dilution act either as spin defects decoupled from the surrounding ions, or generate orbital polarons along $d^3$-$d^4$ hybrid bonds. The exchange on these bonds determines which orbital is occupied by a doublon on the host site. In case of charge dilution by $3d^2$ impurities additional $\propto T_i^+T_j^+$ terms arise which enhance orbital fluctuations. We show that such terms may radicall…
Evidence of a non-conservative mass transfer in the ultra-compact X-ray source XB 1916-053
2020
The dipping source XB 1916-053 is a compact binary system with an orbital period of 50 min harboring a neutron star. Using ten new {\it Chandra} observations and one {\it Swift/XRT} observation, we are able to extend the baseline of the orbital ephemeris; this allows us to exclude some models that explain the dip arrival times. The Chandra observations provide a good plasma diagnostic of the ionized absorber and allow us to determine whether it is placed at the outer rim of the accretion disk or closer to the compact object. From the available observations we are able to obtain three new dip arrival times extending the baseline of the orbital ephemeris from 37 to 40 years. From the analysis…
Wpływ podstawienia karbazolu pierścieniem fulwenowym na ich strukturę elektronową
2019
Na właściwości optoelektroniczne układów organicznych, w znacznym stopniu ma wpływ ich struktura elektronowa. Poznanie zatem czynników determinujących ich strukturę elektronową stanowi istotny punkt wyjścia w badaniach nad możliwościami potencjalnego ich zastosowania. Wśród wielu narzędzi, którymi można modyfikować π-elektronową delokalizację w układach aromatycznych jest efekt podstawnikowy. Rolę podstawników mogą również pełnić układy cykliczne a w szczególności te, które nie spełniają reguły Hückla, gdyż ich dążność do stanu aromatycznego, jest czynnikiem generującym ruch elektronów π w strukturach. Przykładem takiego pierścienia może być fulwen, który posiada 5 elektronów π i w miarę mo…
Rola efektu podstawnikowego w sprzężeniu π-elektronowym w N-podstawionym karbazolu
2019
Modyfikacja właściwości optoelektronowych materiałów organicznych w wielu przypadkach sprowadza się do wywołania zmian w ich strukturze elektronowej, a w szczególności w π-elektronowej delokalizacji w obrębie całej molekuły. Dużą uwagę zajmują w tych badaniach układy skondensowane zawierające pierścienie aromatyczne, niearomatyczne oraz hetero atomy. Do układów tych można zaliczyć, między innymi, karbazol i jego pochodne, który znajduje zastosowanie w organicznych materiałach optycznych i elektronowych. W niniejszej publikacji zaprezentowano wyniki z przeprowadzonych badań nad wpływem podstawienia pierścienia fulwenowego na atomie azotu oraz podstawników o zróżnicowanym charakterze elektron…
Finite-frequency spin susceptibility and spin pumping in superconductors with spin-orbit relaxation
2020
Static spin susceptibility of superconductors with spin-orbit relaxation has been calculated in the seminal work of A.A. Abrikosov and L.P. Gor'kov [Sov. Phys. JETP, {\bf 15}, 752 (1962)]. Surprisingly the generalization of this result to finite frequencies has not been done despite being quite important for the modern topic of superconducting spintronics. The present paper fills this gap by deriving the analytical expression for spin susceptibility. The time-dependent spin response is shown to be captured by the quasiclassical Eilenberger equation with collision integrals corresponding to the ordinary and spin-orbit scattering. Using the developed formalism we study the linear spin pumping…
Proximity Effect in Superconducting Heterostructures with Strong Spin-Orbit Coupling and Spin Splitting
2019
It has been shown that singlet Cooper pairs can be converted into triplet ones and diffuse into a ferromagnet over a long distance in a phenomenon known as the long-range proximity effect (LRPE). This happens in materials with inhomogeneous magnetism or spin-orbit coupling (SOC). Most of the previous studies focus on the cases with small SOC and exchange field. However, the physics was not clear when SOC and exchange field strength are both much greater than the disorder strength. In this work, we consider a two dimensional system with a large Rashba-type SOC and exchange field in the case where only one band is partially occupied. We develop a generalized quasiclassical theory by projectin…
The resonant state at filling factor {\nu} = 1/2 in chiral fermionic ladders
2017
Helical liquids have been experimentally detected in both nanowires and ultracold atomic chains as the result of strong spin-orbit interactions. In both cases the inner degrees of freedom can be considered as an additional space dimension, providing an interpretation of these systems as synthetic ladders, with artificial magnetic fluxes determined by the spin-orbit terms. In this work, we characterize the helical state which appears at filling $\nu=1/2$: this state is generated by a gap arising in the spin sector of the corresponding Luttinger liquid and it can be interpreted as the one-dimensional (1D) limit of a fractional quantum Hall state of bosonic pairs of fermions. We study its main…
Orbitotomía supero medial: nuevos límites en el abordaje endonasal expandido transetmoidal
2015
Introducción: Los límites de los abordajes endonasales endoscópicos expandidos (AEEE) no están delimitados y continúan en constante evolución. El límite de la extensión lateral en el plano coronal del AEEE transetmoidal descrito hasta el momento viene determinado por la unión del techo de las fóveas etmoidales con la lámina papirácea. Objetivos: Este trabajo se basa en la hipótesis fundamental de que la resección de lesiones situadas en la base craneal anterior, concretamente en la porción formada por el hueso frontal y asentadas más allá de las láminas papiráceas, pueden ser abordadas de forma completamente endonasal endoscópica. La hipótesis operativa considera que es posible mediante la …
Synthesis, X-Ray Structure, Tautomerism Aspect, and Chemical Insight of The 3-(1H-Indol-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-ol
2021
The 3-(1H-indol-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-ol 2 was obtained exclusively in the enol configuration starting from triazolyl-indole derivative 1 and alkyl halo-esters in the presence of K2CO3. Chemical structure elucidations with the aid of physicochemical characterizations were used to predict its molecular structure while single crystal X-ray diffraction technique was used to shed the light on the supramolecular structure of 2. DFT calculations agreed very well with the reported X-ray structure where the most stable form thermodynamically is the enol form. Its optimized geometry agreed very well with the experimental structure where the correlation coefficients betwe…
Noninvasive neurostimulation methods for migraine therapy: The available evidence.
2016
Background Migraine is one of the most disabling neurological disorders. The current pharmacological armamentarium is not satisfying for a large proportion of patients because the responder rate does not exceed 50% on average and the most effective drugs often induce intolerable side effects. During recent years, noninvasive central and peripheral neuromodulation methods have been explored for migraine treatment. Overview A review of the available evidence suggests that noninvasive neuromodulation techniques could be beneficial for migraine patients. The transcranial stimulation methods allow modulating selectively cortical activity and can thus be curtailed to the patient’s pathophysiologi…