We use infrared (IR) and Raman spectroscopies to investigate the optically active phonon modes in InP nanoparticles and InP/II–VI core-shell nanoparticles fabricated by similar colloidal chemistry methods. The IR transmission spectra of several InP nanoparticle samples exhibit a common absorption feature, which we assign to the Fröhlich mode. The Raman results for the same samples show transver...

Hyperbolic materials exhibit sub-diffractional, highly directional, volume-confined polariton modes. Here we report that hyperbolic phonon polaritons allow for a flat slab of hexagonal boron nitride to enable exciting near-field optical applications, including unusual imaging phenomenon (such as an enlarged reconstruction of investigated objects) and sub-diffractional focusing. Both the enlarge...

Gallium arsenide nanowires were synthesized by gallium-assisted molecular beam epitaxy. By varying the growth time, nanowires with diameters ranging from 30 to 160 nm were obtained. Raman spectra of the nanowire ensembles were measured. The small linewidth of the optical phonon modes agree with an excellent crystalline quality. A surface phonon mode was also revealed, as a shoulder at lower fre...

Conventional phonon Raman spectroscopy is a powerful experimental technique for the study of crystalline solids that allows crystallography, phase and domain identification on length scales down to approximately 1 microm. Here we demonstrate the extension of tip-enhanced Raman spectroscopy to optical crystallography on the nanoscale by identifying intrinsic ferroelectric domains of individual B...

We investigate coherent Bloch oscillations in GaAs/AlxGa1-xAs superlattices with electronic miniband widths larger than the optical phonon energy. In these superlattices the Bloch frequency can be tuned into resonance with the optical phonon. Close to resonance a direct coupling of Bloch oscillations to LO phonons is observed which gives rise to the coherent excitation of LO phonons. The densit...

Superconductivity of n-doped SrTiO3, which remained enigmatic for half a century, is treated as a particular case of nonadiabatic phonon pairing. Motivated by experiment, we suggest the existence of the mobility edge at some dopant concentration. The itinerant part of the spectrum consists of three conduction bands filling by electrons successively. Each subband contributes to the superconducti...

It is shown that current saturation in semiconducting carbon nanotubes is indistinguishable from metallic nanotubes if the carrier density is above a critical value determined by the bandgap and the optical phonon energy. This feature stems from the higher number of current-carrying states in the semiconducting tubes due to the van Hove singularity at the band edge. Above this critical carrier ...

Abstract. We use a fully self-consistent three-dimensional quantum mechanical transport formalism to examine the performance of InAs based quantum wire transistors both in the ballistic limit and with phonon scattering included. We present a method for the inclusion of polar optical phonon scattering as a real-space self-energy term. We find that the ballistic performance of the devices can be ...

The coupling of Bloch oscillations to longitudinal optical phonons is investigated in a narrow-well In0.53Ga0.47As/In0.52Al0.48As superlattice. A strong increase of coherent phonon amplitudes is observed when the Bloch oscillations are subsequently tuned into resonance with different optical phonon modes. The rapid dephasing of the Bloch oscillations due to field induced tunneling from the weak...

We propose theory for a reversible quantum transducer connecting superconducting qubits and optical photons using acoustic waves in piezoelectrics. The proposed device consists of an integrated acousto-optic resonator that utilizes stimulated Brillouin scattering for phonon-photon conversion and piezoelectric effect for coupling of phonons to qubits. We evaluate the phonon-photon coupling rate ...