arXiv subjects

A. V. Uskov

Publications and source records attributed to A. V. Uskov.

3 recordsLinked to original sources

arXiv2021

Surface and volume photoemission from metal nano-particles with electron mass discontinuity

Quantum efficiencies of surface (SPE) and volume (VPE) photo-emissions from metal nanoparticles are calculated by quantum mechanical perturbation theory and compared with each other. Along with discontinuities in the potential barrier and dielectric function, the discontinuity in electron effective mass on the metal-environment interface is taken into account. General formulas for quantum efficiencies of SPE and VPE are derived. An example of spherical gold particles with rectangular potential barrier on the interface is considered, analytical formulas for quantum efficiencies of SPE and VPE on the red border of photoemission are derived. It is found that the efficiency of SPE is less decreased with the reduction of the electron effective mass than the efficiency of VPE, so SPE is more efficient that VPE for small particles and large discontinuity in effective mass. Nanoparticle size, when SPE is more efficient than VPE, is found to be tens of nm or less.

cond-mat.mes-hall↗

arXiv2017

NMR studies of the topological insulator Bi2Te3

Te NMR studies were carried out for the bismuth telluride topological insulator in a wide range from room temperature down to 12.5 K. The measurements were made on a Bruker Avance 400 pulse spectrometer. The NMR spectra were collected for the mortar and pestle powder sample and for single crystalline stacks with orientations c parallel and perpendicular to field. The activation energy responsible for thermal activation. The spectra for the stack with c parallel to field showed some particular behavior below 91 K.

cond-mat.mes-hall↗

arXiv2000

Dephasing times in quantum dots due to elastic LO phonon-carrier collisions

Interpretation of experiments on quantum dot (QD) lasers presents a challenge: the phonon bottleneck, which should strongly suppress relaxation and dephasing of the discrete energy states, often seems to be inoperative. We suggest and develop a theory for an intrinsic mechanism for dephasing in QD's: second-order elastic interaction between quantum dot charge carriers and LO-phonons. The calculated dephasing times are of the order of 200 fs at room temperature, consistent with experiments. The phonon bottleneck thus does not prevent significant room temperature dephasing.

cond-mat↗