Dynamics of Electrons in Graded Semiconductors
نویسنده
چکیده
I present a theory of electron dynamics in semiconductors with slowly varying composition. I show that the frequency-dependent conductivity, required for the description of transport and optical properties, can be obtained from a knowledge of the band structures and momentum matrix elements of homogeneous semiconductor alloys. New sum rules for the electronic oscillator strengths, which apply within a given energy band or between any two bands, are derived, and a general expression for the width of the intraband absorption peak is given. Finally, the low-frequency dynamics is discussed, and a correspondence with the semiclassical motion is established. [S0031-9007(96)02038-8]
منابع مشابه
Dynamics of Entanglement between Linearly Polarized Photons and π -Electrons in Graphene
In the present article we report the dynamical behavior of entanglement between π-electrons and photons in Graphene. It is shown that the degree of such entanglements depend on the orientation of π-electron momenta relative to the photonic polarization. Moreover, we show that as the detuning between the π-electron transition frequencies and that of the photons is increased, the degree of entang...
متن کاملDynamics of Electrons in Free Electron Laser with Square Core Waveguides
Due to sensitive and important applications of free-electron laser in industry and medicine, improvement of the power and efficiency of laser has always been emphasized. Therefore, understanding the created field and examining the properties of the field in waveguides with different shapes and studying the sustainability of electrons movement are particularly important. In this study, the beh...
متن کاملDirect and simultaneous observation of ultrafast electron and hole dynamics in germanium
Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and sim...
متن کاملMany–body Correlation Effects in the Ultrafast Nonlinear Optical Response of Confined Fermi Seas
The dynamics of electrons and atoms interacting with intense and ultrashort optical pulses presents an important problem in physics that cuts across different materials such as semiconductors and metals. The currently available laser pulses, as short as 5 fs, provide a time resolution shorter than the dephasing and relaxation times in many materials. This allows for a systematic study of many–b...
متن کاملUltrafast electron transport in layered semiconductors studied with femtosecond-laser photoemission
Femtosecond-laser photoemission was used to investigate the electron dynamics in the layered semiconductors MoSe2 and WSe2. Photoexcitation with 200-fs pulses of 2.03 eV light creates an electron gas with significant excess energy. Our measurements reveal a strong transient enhancement in the diffusive transport of the most energetic electrons relative to the conduction-band minimum. Additional...
متن کامل