We presented invited talk on nonequilibrium quasiparticle (QP) dynamics in underdoped Bi2212 crystals using ultrafast optical spectroscopy, which allows to analyze the dynamics associated with the superconducting (SC) and psuedogap (PG) QPs independently.
B.04 Guest lecture
COBISS.SI-ID: 26664743Invited talk with presentation of coherent trajectories through phase transitions in layered chalcogenides and related systems
B.04 Guest lecture
COBISS.SI-ID: 26613543The properties of the resistive state of the narrow superconducting channels of different lengths are investigated by direct numerical integration of the time-dependent Ginzburg-Landau equations (TDGLEs). We have demonstrated that singularities of the current-voltage characteristics correspond to a number of different bifurcation points of the TDGLEs, and we have revealed the types of the bifurcations. Then we theoretically study how the dynamics of the resistive state in narrow superconducting channels shunted by an external resistor depends on channel length, applied current, and penetration depth of the electric field in nonequilibrium superconductors. We show that changing penetration depth dramatically affects both the behaviour of the CVCs of the superconducting channels and the dynamics of their order parameter.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 27239975We investigate the current-voltage characteristics (CVC) of long and narrow superconducting channels using the time-dependent Ginzburg-Landau equations for complex order parameter. We show that the steps in the CVC can be associated with bifurcations of either steady state or oscillatory solution. We also study the dynamics of the resistive state in a narrow superconducting channel shunted by an external resistor, and explore the bifurcation mechanisms which are responsible for the formation and evolution of phase slip centers and which are also involved in the hysteresis of current-voltage characteristics. Last, we develop the theory where both nonthermal electron and phonon distribution functions are obtained by the solution of linearized kinetic equations with electron-phonon and phonon-electron collision integrals. We simplify these equations in the case of high-temperature and of low-temperature relaxation. Accurate solution of the kinetic equations leads to the distribution function which is very similar to that observed in time-resolved photoemission experiments.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 268676096The subject of invention is a method for a synthesis of one-dimensional structures such as nanowires, microwires and nanobelts 4d and 5d transitional metals (Nb, Mo Ta, W). The invention belongs to the field of inorganic chemistry and chemistry of transition metals. The invention refers to a synthesis of quasi-one dimensional structures of transitional metals by using a method of conversion of quai one-dimentional scompounds with a submicron cross-section of nanowires described with formula M6CyHz, 8,2(y+z 10, where M is a transition metal (Nb, Mo Ta, W), C is a chalcogen (sulphur (S), selenium (Se), tellurion (Te)); H is a halogen (iodine (I)) by heating in the presence of hydrogen.
F.32 International patent
COBISS.SI-ID: 26468135