Related papers: Negative high-frequency differential conductivity …
We report the operation of a Bloch oscillator. The active medium was a staticvoltage driven, doped GaAs/AlAs superlattice which was electromagnetically coupled to a resonator. The oscillator produced tuneable microwave radiation (frequency…
We examine the effect of fractionality on the bloch oscillations (BO) of a 1D tight-binding lattice when the discrete Laplacian is replaced by its fractional form. We obtain the eigenmodes and the dynamic propagation of an initially…
We consider high-frequency local vibrations anharmonically coupled with low-frequency modes in a planar lattice of adsorbed molecules. The effect of lateral intermolecular interactions on the spectral line shape for local vibrations is…
Fibonacci system with both diagonal and off-diagonal disorder is mapped to a model with dimer type 'defects'. The model exhibit resonance transition corresponding to zero reflectance condition resulting in extended states in the system.…
Band structures encode electronic, optical, and acoustic properties of matter and can serve as an essential tool in material discovery and design. Dispersion anomalies -- sharp, non-standard features in the frequency-wavenumber relation --…
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…
We study both analytically and numerically phonon transmission fluctuations and localization in partially ordered superlattices with correlations among neighboring layers. In order to generate a sequence of layers with a varying degree of…
The continuum limit of a recently-proposed model for charge transport in resonant-tunneling semiconductor superlattices is analyzed. It is described by a nonlinear hyperbolic integrodifferential equation on a one-dimensional spatial…
Atomic-scale variations in semiconductor heterostructures, arising from strain, interfaces, and compositional modulation, strongly influence electronic band dispersion but remain difficult to probe and compare using first-principles methods…
We demonstrate semiconductor superlattices or nanocavities as narrow band acoustic transducers in the sub-terahertz range. Using picosecond ultrasonics experiments in the transmission geometry with pump and probe incident on opposite sides…
Longitudinal spin transport in diluted magnetic semiconductor superlattices is investigated theoretically. The longitudinal magnetoconductivity (MC) in such systems exhibits an oscillating behavior as function of an external magnetic field.…
We study the quantum dynamics of soliton-like domain walls in anisotropic spin-1/2 chains in the presence of magnetic fields. In the absence of fields, domain walls form a Bloch band of delocalized quantum states while a static field…
The inelastic x-ray scattering spectrum for phonons of $\Delta_{1}$-symmetry including the CuO bond-stretching phonon dispersion is analyzed by a Lorentz fit in HgBa$_{2}$CuO$_{4}$ and Bi$_{2}$Sr$_{2}$CuO$_{6}$, respectively, using recently…
We experimentally demonstrate broadband waveguide crossing arrays showing ultra low loss down to $0.04\,$dB/crossing ($0.9\%$), matching theory, and crosstalk suppression over $35\,$dB, in a CMOS-compatible geometry. The principle of…
We report on theoretical analysis of large amplitude current dynamics due to Bragg reflections in carbon nanotubes exposed to an external electric field. Using the kinetic equation with constant relaxation time, an analytical expression for…
Lattice-matched heterovalent alloys and superlattices have some unique physical properties. For example, their band gap can change by a large amount without significant change in their lattice constants, thus they have great potential for…
Geometric analogs of Bloch oscillations studied so far have relied on Berry curvature. We show that a weakly inhomogeneous electric field adds a distinct quantum-metric term to semiclassical wavepacket dynamics, generating an oscillatory…
We demonstrate that the strong anomalies in the high frequency LO-phonon spectrum in cuprate superconductors can in principle be explained by the enhanced electronic polarizability associated with the self-organized one dimensionality of…
We discuss an effect of dc current and dc voltage (stopping bias) generation in a semiconductor superlattice subjected by an ac electric field and its phase-shifted n-th harmonic. In the low field limit, we find a simple dependence of dc…
We study the consequences of negative differential electron mobility in insulated gate field effect transistors (FETS) using the field model. We show that, in contrast to the case of the monotonic velocity saturation model, the field…