1. An electron energy level correlation function for disordered two-dimensional systems has been investigated. In a high-frequency limit, an unexpected universality has been found: the correlation function is expressed in terms of the Euler characteristic of the surface, i.e., it depends on the system topology [5]. 2. In a series of papers [8, 11, 12] a problem of a nonlinear response of mesoscopic systems on an external alternating field has been considered. It has been shown [8] that the dynamical description (restricted to the model of non-interacting electrons) suffers from intrinsic singularities. A consistent kinetic theory has been developed with taking into account the electron-phonon interaction. General expressions for a rectified (direct)current have been derived. Solving the quantum kinetic equation we have obtained an expression for an effective electron temperature and estimated overheating effects in the pumped electron system [12]. For mesoscopic metal rins placed in a magnetic field and pumped by an alternating external field, a correlation function <I(F)I(F')> of a time-independent current (including an equilibrium persistent and a rectified field induced counterparts) has been obtained. The symmetry of this function with respect to the magnetic flux F is shown to be drastically dependent on the spectral width of the pump field [11]. 3. Classical diffusion in systems with varying boundaries has been studied; classical analogs of quantum weak localization effects have been found [10]. 4. A diffusion model for phase fronts evolution in solid state chemical reactions has been suggested [1]. 5. A model for a hysteretic cyclotron resonance in GaAs/AlGaAs structures has been put forward. The model takes into account a change of the electron density and describes basic features of the observed effects [6]. 6. A lattice model has been suggested for an electron-hole system in disordered coupled quantum wells. It has been shown that a strong disorder suppresses the formation of excitons [2,4] 7. A formalism has been developed to describe an electron (exciton) with the electron-phonon interaction restricted to a local center [7,9]; an exact description of the second harmonic generation has been given for a charge-transfer exciton interacting with phonons. Optical nonlinearities of a semiconductor quantum dot covered by an organic layer have been investigated [12]. |
References
[1] V.I. Yudson, M. Schulz, and S. Stepanow, "Dynamics and roughness of reaction fronts in heterogeneous solid-state chemical reactions"; Phys.Rev. E 57 , 5053-5059 (1998).
[2] V.I. Yudson and M. Singh, "A lattice gas model for electron-hole coupling in disordered media"; Phys.Rev. B 58 , 16202-16208 (1998).
[3] A.Engelmann, V.I. Yudson, and P. Reineker, "Enhanced optical nonlinearity of hybrid excitons in an inorganic semiconducting quantum dot covered by an organic layer"; Phys.Rev. B 57 , 1784-1790 (1998).
[4] W. Lau, V.I. Yudson, and M. Singh,"Study of the lattice-gas model of electron-hole coupling in disordered semiconductors"; Phys.Let. A 250 , 196-200 (1998).
[5] V.E. Kravtsov and V.I. Yudson, "Topological Spectral Correlations in 2D Disordered Systems"; Phys.Rev.Lett. 82 , 157 (1999).
[6]. B.M. Ashkinadze and V.I. Yudson, "Observation of a Hysteretic Microwave Cyclotronlike Resonance in a Laterally Confined Two-Dimensional Electron Gas";Phys.Rev.Lett., 83 , 812 (1999).
[7] V. I. Yudson and M. Singh, "Electron Scattering at a Center with Phonon Degrees of Freedom"; Phys.Lett. A 264 , 198-201 (1999).
[8] ] V.I. Yudson, E. Kanzieper , and V.E. Kravtsov,"Limits of the dynamical approach to the nonlinear response of mesoscopic systems"; Phys.Rev. B, .64 , 045310 (2001).
[9]. P. Reineker and V.I. Yudson, "Second Harmonic Generation by Charge-Transfer Excitons Interacting with Phonons"; Phys.Rev. B 63 , 233101 (2001).
[10] V.I. Yudson and P. Reineker,“Classical diffusion in channels with a spatially varying cross section"; Phys.Rev. E 64 , 031108 (2001).
[11] V.I. Yudson, "Variance of direct current in mesoscopic rings" Phys.Rev. B 65, 115309 (2002).
[12] V.I. Yudson and V.E. Kravtsov, "Electron kinetics in isolated mesoscopic rings driven out of equilibrium"; Phys.Rev. B 67 , 155310 (2003)