Stochastic Carrier Dynamics in Semiconductor Superlattices
T.M. Fromholda, S. Bujkiewicza, A. Patanèa, S.P. Stapletona, D. Sherwooda, D. Fowlera, J. Coopera, L. Eavesa, A.E. Belyaeva, A.A. Krokhina,b,c, A. Neumanna, P.B. Wilkinsona, N.S. Sankeshwara, M. Heninia and F.W. Shearda
aSchool of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK,
bInstituto de Fisica, Universidad Autonoma de Puebla, Puebla 72570, Mexico,
cCenter for Nonlinear Science, University of North Texas, P.O. Box 5368, Denton, Texas 762203, USA
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Received: 19 05 2005;
We explore a new regime of hot carrier dynamics, in which electrons in a superlattice miniband exhibit a unique type of stochastic motion when a magnetic field is tilted at an angleθ to the superlattice axis. Remarkably, the dynamics of a miniband electron in a tilted magnetic field reduce to a one-dimensional simple harmonic oscillator, of angular frequencyωC cosθ, whereωC is the cyclotron frequency, driven by a time-dependent plane wave whose angular frequency equals the Bloch frequencyωB. At bias voltages for whichωB=nωC cosθ, where n is an integer, the electron orbits change from localised Bloch-like trajectories to unbounded stochastic orbits, which diffuse rapidly through intricate web patterns in phase space. To quantify how these webs affect electron transport, we make drift-diffusion calculations of the current-voltage curves including the effects of space-charge build up. When the magnetic field is tilted, our simulations reveal a large resonant peak, which originates from stochastic delocalisation of the electron orbits. We show that the corresponding quantised eigenstates change discontinuously from a highly localised character when the system is off resonance to a fully delocalised form when the resonance condition is satisfied.
DOI: 10.12693/APhysPolA.109.43
PACS numbers:73.20.At, 73.21.Cd