The effect of a quantizing electric field on the transverse mobility of electrons in a superlattice
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MENSIONAL SYSTEMS
The Effect of a Quantizing Electric Field on the Transverse Mobility of Electrons in a Superlattice D. V. Zav’yalov^, S. V. Kryuchkov, and N. E. Meshcheryakova Volgograd State Pedagogical University, Volgograd, 400131 Russia ^e-mail: [email protected] Submitted February 21, 2006; accepted for publication April 26, 2006
Abstract—The effect of a quantizing static electric field parallel to the axis of a semiconductor superstructure on the charge-carrier mobility in the direction perpendicular to this axis is studied. The transverse conductivity of charge carriers was calculated on the basis of a quantum-mechanical kinetic equation. Using the results of the numerical analysis, the dependences of the time of the carriers’ momentum relaxation on their transverse energy and also the dependences of the charge-carrier mobility on the strength of the longitudinal quantizing electric field were plotted. It is shown that the dependence of the density of current flowing perpendicularly to the superlattice axis on the strength of the longitudinal electric field is oscillatory. PACS numbers: 72.20.Ht, 73.21.Cd, 73.40.Kp, 73.63.-b DOI: 10.1134/S1063782606120104
The general theory of transport phenomena for semiconductors in a high static electric field was developed by Bryxin et al. [1–3] and was then used with good results in studies of electrical properties of semiconductor superlattices (SLs). In particular, the effect of a monochromatic radio-frequency (RF) electric field on the SL conductance was considered and the phenomena of absolute negative conductance, complete self-induced transparence, and oscillatory dependence of current on the RF field strength were predicted [4–7]. The effect of cnoidal electromagnetic waves on the SL conductance in a quantizing electric field was studied by Zav’yalov et al. [8]. In all the above-cited publications, only the longitudinal conductance was studied; i.e., the current flowing along the SL axis under the effect of a static electric field was calculated. At the same time, the transport of charge carriers in the structure plane perpendicular to the axis was not discussed. However, it is difficult experimentally to ensure an exact orientation of the electric-field vector E along an arbitrary specified direction (for example, along a crystallographic axis or along the SL axis). Therefore, a small transverse component of the vector E always exists. The problem of discrepancy between the vector E and the crystal axis was mentioned for the first time by Ktitirov et al. [9]. The discussion of this issue is still continuing. For example, Suris [10] noted that there is a heavy dependence of the spectrum of the Bloch oscillations on the electric-field orientation. Zav’yalov et al. [11] predicted resonance features of the SL transverse magnetoconductance under conditions of Stark quantization. In addition, the mobilities of the charge carriers (and, correspondingly, their current) in the plane of the SL layers are much higher than their mobilities along
the SL axis, which make
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