Chaotic dynamics in terahertz-driven semiconductors with negative effective mass

J. C. Cao

H. C. Liu

Institute for Microstructural Sciences, National Research Council, Ottawa, Ontario, Canada K1A 0R6

Department of Applied Physics, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai, 200030, People's Republic of China
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Metallurgy, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, People's Republic of China

A. G. U. Perera

Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303

Abstract:

We report on a detailed theoretical study of current self-oscillations and chaotic dynamics in negative effective mass (NEM) p⁺pp⁺ diodes driven by dc and ac electric fields with a terahertz (THz) frequency. An "N-shaped" velocity-field relation is yielded by using the nonparabolic balance-equation theory with a realistic treatment of carrier scatterings by impurity, acoustic phonon, and optic phonon. The dependence of the self-oscillating mode and its frequency on the dc bias, doping concentration, and lattice temperature is examined in detail. The THz-driven p⁺pp⁺ NEM diodes can produce a cooperative nonlinear oscillatory mode which leads to very complicated chaotic dynamics with the dc bias, ac amplitude, and ac frequency as the controlling parameters. The transitions between the periodic and chaotic states are carefully studied by different chaos-detecting methods, such as phase portrait, Poincaré bifurcation diagram, power spectrum, and first return map. The resulting power spectrum bifurcation diagram displays a very complicated mosaic structure with a self-similar emergence of high-order mixing frequencies. ©2001 The American Physical Society

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