相关论文: Terahertz Bloch oscillator with suppressed electri…

Electrons performing Bloch oscillations in an energy band of a dc-biased superlattice in the presence of weak dissipation can potentially generate THz fields at room temperature. The realization of such Bloch oscillator is a long-standing…

In two recent Letters [Phys. Rev. Lett. 90, 046806; Phys. Rev. Lett. 94, 057408], Hirakawa et al. investigate the emission of coherent terahertz (THz) radiation from optically excited superlattices. The authors interpret the spectra of the…

Ultrafast charge transport in strongly biased semiconductors is at the heart of highspeed electronics, electro-optics, and fundamental solid-state physics. Intense light pulses in the terahertz (THz) spectral range have opened fascinating…

A semiconductor superlattice with hot electron injection into the miniband is considered. The injection changes the stationary distribution function and results in a qualitative change of the frequency behaviour of the differential…

We show that a tilted magnetic field transforms the structure and THz dynamics of charge domains in a biased semiconductor superlattice. At critical field values, strong coupling between the Bloch and cyclotron motion of a miniband electron…

In a semiconductor superlattice with long scattering times, damping of Bloch oscillations due to scattering is so small that convective nonlinearities may compensate it and Bloch oscillations persist even in the hydrodynamic regime. In this…

We study theoretically the feasibility of amplification and generation of terahertz radiation in dc-ac-driven semiconductor superlattices in the absence of electric domains. We find that if in addition to dc bias a strong THz pump field is…

We present a concept of terahertz oscillations in superlattices that are generated under conditions apparently different from standard Bloch oscillations. These oscillations are induced when crossed magnetic and electric fields are applied…

In a semiconductor superlattice with long scattering times, damping of Bloch oscillations due to scattering is so small that nonlinearities may compensate it and Bloch oscillations persist even in the hydrodynamic regime. To demonstrate…

Semiconductor superlattices are interesting for two distinct reasons: the possibility to design their structure (band-width(s),doping, etc.) gives access to a large parameter space where different physical phenomena can be explored.…

We theoretically analyze the influence of magnetic field on small-signal absorption and gain in a superlattice. We predict a very large and tunable THz gain due to nonlinear cyclotron oscillations in crossed electric and magnetic fields. In…

We use an analytic perturbation expansion for the two-band system of tight binding electrons to discuss Bloch oscillations and Zener tunneling within this model. We make comparison with recent numerical results and predict analytically the…

We study the response of low-dimensional semiconductor superlattices to strong terahertz fields on condition of a strong suppression of inelastic scattering processes of electrons caused by the polar-optical phonons. For our study we employ…

We consider terahertz absorption and gain in a single miniband of semiconductor superlattice subject to a bichromatic electric field in the most general case of commensurate frequencies of the probe and pump fields. Using an exact solution…

We investigate the electronic Bloch oscillation in bilayer graphene gradient superlattices using transfer matrix method. By introducing two kinds of gradient potentials of square barriers along electrons propagation direction, we find that…

We present a time-domain analysis of carrier dynamics in a semiconductor superlattice with two minibands. Integration of the density-matrix equations of motion reveals a number of new features: (i) for certain values of the applied static…

We present theoretical and numerical results on the dynamics of ultracold atoms in an accelerated single- and double-periodic optical lattice. In the single-periodic potential Bloch oscillations can be used to generate fast directed…

Achieving Bloch oscillations of free carriers under a direct current, a long-sought-after collective many-body behavior, has been challenging due to stringent constraints on the band properties. We argue that the flat bands in moir\'e…

It is well known that a particle in a periodic potential with an additional constant force performs Bloch oscillations. Modulating every second period of the potential, the original Bloch band splits into two subbands. The dynamics of…

The problem of Bloch electrons in two dimensions subject to magnetic and intense electric fields is investigated. Magnetic translations, electric evolution and energy translation operators are used to specify the solutions of the…