PHOTOVOLTAIC EFFECT AT SPIN RESONANCE IN QUANTUM MAGNETIC FIELD

N. N. Chernyshov, A. V. Belousov, M. A. F. Alkhawaldeh, V. M. Pisarenko, I. V. Rogozin The Federal State Budget Educational Institution of Higher Education “Belgorod State Technological University named after V. G. Shukhov”. 46, Kostyukova street, Belgorod, 308012, Russian Federation Kharkov National University of Radio Electronics 14, prospect of Science, Kharkov, 61166, Ukraine E-mail: mykola.chernyshov@nure.ua

The phenomenon of combined resonance (light absorption at the expense of the electric component of a electromagnetic wave, which is caused by election transitions with a spin-flip) still continues being in a sphere solid state physics shows interest. For the interference phenomenon of magnet and electrode-pole resonances in the Foygt configuration in crystals without an inversion centre. Investigating photovoltaic effect (PVE) is of special interest. Both light absorption and PVE are calculated by the absence of the medium central symmetry. The aim of the work is theoretical and experimental investigation of photovoltaic effect in spin resonance. Practical value consists in development of methods for the investigation of conditioning parameters, because the terms in the Hamiltonian can lead to electric-dipole transitions and the photocurrent.
1. Light polarization. Let us consider a current along the direction of a magnetic field H  in propaganding light along the same direction (Faraday geometry). The light polarization and orientation H  with respect to crystallographic axes are considered to be arbitrary. Suppose, the conditions are met which comply with the super quantum limit: .
Is the energy of a spin transition, F E  is the Ferni level counted from the bottom spin sub band, B µ is a Bohr magneton, g is a factor, A  are vector potentials of a static uniform magnetic field and a electromagnetic wave [1] is the potential energy of interaction of elections with chaotically distributed impurities ( i r  is a coordinate of the i-th impurity centre). The Hamiltonian of the system considered takes the form , 2  The existence of a current along the direction of the field H  requires the address of transition probability as a function of a longitudinal momentum .
z P As we are interested in election transitions, within the Landau level at n, we will omit this index in all the quantities. The part of the distribution function, potentially odd in impulse, contributing to the current, can emerge as a result of the oddness of a generation function. On the first order of perturbation theory the asymmetric part of a transition probability can appear at the expense of the interference of the contributions F 1 and F 2 . The terms have been analyzed that emerge due to the address of scattering probability on impurities in p  . At has been found that in the super quantum limit (unlike the case of absence H  ). These terms don't result in PVE. The oddness of the generation function is not either available in the parabolic approximation for an election spectrum. With view of the spectrum nonparabolicity the contribution to the current has been found [2; 3] ).
Here P is a delta-function, blurred on the broadening n, ∆ is fuming out of resonance.

Asymmetric probability.
In addition to the considered input to the current, there are more components associated with inputs in asymmetric probability of a transition with spin flip from the interaction of electrons with impurities. It may seem that transitions with spin flip, with the participation of impurities are not resonant, as it does not maintain .
p  However, PVE in this case is determined by the resonance in the intermediate state. The reason for this is similar to the reason of occurrence of resonance PVE in the quantum film. These inputs arise when considering the interference of transition amplitudes of first and second order. For the case ) (  Theory of the effect is well described, highlighting the observed polarization dependence in the considered orientations of H  relative to the crystallographic directions [5]. Comparison of theoretical and experimental values of the signals for the even configuration from the resonance the input allows you to define the parameters . ; S g a The values of these parameters are in good agreement with their values, calculated in Kane model. Theoretical value the odd input by ∆ input is by almost three orders higher than experimentally observed expected value. This is partly due to the fact that the heterogeneity of H  in the volume occupied by the sample, leads to the suppression of the alternating signal and has little effect on the value of constant value of the input. Inputs not taken into account by the theory describing the odd ∆ peak are possible. Impurity peaks behave as peak spin resonance by free carriers. Between bound states only internal transitions are allowed. In such transitions of free electrons appear due to the auto-ionization processes. The input of the states in the PVE stems from the fact that the excited impurity states are intermediate and the final state is free.
3. Strengthening of the PVE in 2D-disordered medium. Let's consider the distribution of E  in a weakly absorbing environment. In randomly inhomogeneous macroscopic mediums constructed of non-absorbent microscopic parts, due to the excitation of local plasmons occurs the enhancement of the local electric fields. In this mediums from the average values of the even powers of a module E  differ and are crucial for different nonlinear responses of the system, which leads to their strengthening. A two-phase medium consisting of two statistically ε with opposite signs. The result is sensitive to the initial value, and at any step isotropy of the system is not observed: .
Thus, the problem reduces to a nonlinear recurrence relation for the dielectric transmittivities.
Conclusion. The article is devoted to the study of PVE in optical transitions between spin sub bands of the Landau levels. Considered geometry, when the polarization is perpendicular, and the current is directed along .
H  The dependence of I  from H  is of resoance character, and contains both even-numbered and oddnumbered field inputs. This character of effects is associated with resonance in an intermediate state and the interference of transition amplitudes of the second-order relativistic inputs to the Hamiltonian function. Practical value and scientific novelty is concluded in the study of PVE at spin resonance. It can complement experiments on light absorption measurement as a method of conditioning parameters, as the same components in the Hamiltonian function can lead to an electric dipole transitions. The article examines PVE in weakly absorbing medium. It is shown that as a result of the divergence of the average square modulus of E  there is an increase in effective PVE.