News (15 Oct 2016 - 2 Dec 2017)

Ultrafast relaxation dynamics

added on 2 December 2017, 13:10

P. Maldonado, K. Carva et al. presented a research on ultrafast relaxation dynamics in metals. They developed an out-of-equilibrium theory that captures the full dynamic evolution of the electronic and phononic populations and provides a microscopic description of the transfer of energy delivered optically into electrons to the lattice.

Handbook of Magnetic Materials

added on 2 December 2017, 13:00

K. Carva, P. Baláž, and I. Radu contributed to the Handbook of Magnetic Materials (vol. 26) with a chapter entitled Laser-Induced Ultrafast Magnetic Phenomena.

Molecules and the graph theory

added on 20 May 2017, 20:35

Ruda Sýkora and Tomáš Novotný present a method based on graph theory for the evaluation of the inelastic propensity rules for molecules exhibiting complete destructive quantum interference in their elastic transmission. The method can be fully automated and they provide a functional website running a code using Wolfram Mathematica which allows everyone to examine their molecules.

Superconducting quantum dot: symmetric vs. asymmetric

added on 18 May 2017, 16:50

A. Kadlecová and her mates studied the Anderson single-level quantum dot attached to two BCS superconducting leads. They revealed that a system with asymmetric tunnel coupling to the leads can be related to the symmetric one. Surprisingly, it is the symmetric case which is the most general, meaning that all physical quantities in the case of asymmetric coupling are fully determined by the symmetric ones.

Interplay between correlation effects and electron pairing

added on 7 January 2017, 10:55

T. Domański et al. studied subgap spectrum of the interacting single-level quantum dot coupled between two superconducting reservoirs, forming the Josephson-type circuit, and additionally hybridized with a metallic normal lead. They quantitatively establish the phase-dependent Kondo temperature and show that it can be read off from the half-width of the zero-bias enhancement in the Andreev conductance in the doublet phase.

Stoner versus Heisenberg

added on 7 January 2017, 10:45

E. Turgut et al. use ultrafast high harmonics to measure time-, energy-, and angle-resolved M-edge magnetic asymmetry spectra for Co films after optical pumping to induce ultrafast demagnetization. They found that the magnon contribution to ultrafast demagnetization is already strong on subpicosecond time scales, while the reduction in exchange splitting persists to several picoseconds.

Noisy metamolecule

added on 18 December 2016, 18:50

T. Chlouba, M. Žonda, and T. Novotný published a comment on recent Letter by Andrianov et al. Using sparse numerical solvers they shown that some of the results in the original letter are incorrect, most likely due to insufficient Monte Carlo sampling. These findings call for a corrected interpretation of the physical behavior of the studied model.

Measurement of the spin penetration length using second-harmonic voltage

added on 16 October 2016, 16:47

A theoretical description of spin current injection from a nonmagnetic layer into a magnetic one is presented by P. Baláž et al. The authors propose a novel method of measurement the transverse spin penetration length in magnetic metals based on second harmonic voltage measurement.

Ab initio theory of laser-induced magnetization in metals

added on 15 October 2016, 16:37

M. Berritta, R. Mondal, K. Carva, and P. M. Oppeneer present in Physical Review Letters a first material specific theory of the magnetization induced by circularly polarized laser light in metals. They show that the inverse Faraday effect leads to the existence of both spin and orbital induced magnetizations which exhibit a surprisingly different behaviour.

Quantum dot attached to superconducting leads

added on 15 October 2016, 16:26

Spin-symmetric solution of an interacting quantum dot attached to superconducting leads is presented by V. Janiš, V. Pokorný, and M. Žonda. They shown that under certain conditions the spin-symmetric solution becomes degenerate.