arXiv subjects

V. M. Bondar

Publications and source records attributed to V. M. Bondar.

4 recordsLinked to original sources

arXiv2013

Polarization dependences of terahertz radiation emitted by hot charge carriers in p-Te

Polarization dependences of the terahertz radiation emitted by hot charge carriers in p-Te have been studied both theoretically and experimentally. The angular dependences of the spontaneous radiation emission by hot carriers is shown to originate from the anisotropy of their dispersion law and the anisotropy of the dielectric permittivity of a tellurium crystal. We have shown that the polarization dependences of radiation are determined by the angle between the crystallographic axis C3 in p-Te and the polarization vector; they are found to have a periodic character.

cond-mat.mes-hall↗

arXiv2010

Effect Of Weak Magnetic Field ($\sim $\,300 Gs) On the Intensity of Terahertz Emission of Hot Electrons in $n$-Ge at Helium Temperatures

Experimental results of studying the effect of a weak magnetic field ($\sim $300 Gs) on the intensity of the terahertz emission ($λ\approx $100 $μ$m) of hot electrons in $n$-Ge (crystallographic orientation $< 1,0,0 >)$ at helium temperatures ($T\sim $5 K) are presented and discussed. It is shown that the strong influence of this field (decrease of the emission intensity by 500$÷$1000{%}) is related to a decrease of the carrier concentration at weak electric fields and the appearance of the magnetoresistance at stronger fields. The longitudinal magnetoresistance becomes significant due to the anisotropy of the energy dispersion law of electrons and a strong deformation of the electron velocity distribution function by the electric field (which is beyond the framework of the diffusion approximation).

quant-ph↗

arXiv2010

Low-Temperature Dependences of the Polarization of Terahertz Emission from $n$-Germanium in Heating Electric Fields

As was noted in [3], in order to verify the assumption that the behavior of the polarization dependences of the terahertz emission by hot electrons from $n$-Ge is determined by the type of carrier scattering, it is necessary to perform temperature measurements of this dependence in the range between the temperatures, where the scattering is determined by impurities and by acoustic lattice vibrations, respectively. The given work presents the results of such investigations.

cond-mat.mtrl-sci↗

arXiv2008

Emission and Absorption of Light by Hot Electrons in Multivalley Semiconductors (TERAHERTZ Range)

The angular dependences of the spontaneous emission by hot electrons in multivalley semiconductors are studied theoretically and experimentally using $n$-Ge as an example. We demonstrate that the change in the scattering mechanism caused by the growth of electron temperature can affect the angular scattering dependence. In the case when the heating field is applied along the symmetry axis of the crystal [for $n$-Ge it is the axis (1,0,0,)], the angular dependence of the emission was observed experimentally for the first time, and the corresponding theory is proposed. When electrons have identical concentration and temperature in every valley, the angular dependence of emission is shown to be related to the violation of symmetry of the energy distribution of electrons (from the theoretical viewpoint, this effect means going beyond the scope of the traditional diffusion approximation).

quant-ph↗