We highlight the importance of carrier-phonon coupling in inorganic lead halide perovskite nanocrystals. The low-temperature photoluminescence (PL) spectrum of CsPbBr3 has been investigated under a nonresonant and a nonstandard, quasi-resonant excitation scheme, and phonon replicas of the main PL band have been identified as due to the Fröhlich interaction. The energy of longitudinal optical (L...

Phonon-assisted exciton transitions in spherical GaAs nanocrystals embedded in SiO2 matrices have been studied by means of selective excitation spectroscopy. The optical and acoustic phononassisted optical transitions appear in the photoluminescence excitation, photoluminescence linenarrowing, and photoluminescence hole-burning spectra at low temperatures. Both direct (zerophonon) and phonon-as...

The following dissertation presents a comprehensive study of the interaction between Dirac fermion quasiparticles (DFQs) and surface phonons on the surfaces of the topological insulators Bi2Se3 and Bi2Te3. Inelastic helium atom surface scattering (HASS) spectroscopy and time of flight (TOF) techniques were used to measure the surface phonon dispersion of these materials along the two high-symme...

Observation of non-equilibrium optical phonons population associated with electron transport in THz quantum cascade lasers is reported. The phonon occupation number was measured by using a combination of micro-probe photoluminescence and Stokes/Anti-Stokes Raman spectroscopy. Energy balance analysis allows us to estimate the phonon relaxation rate, that superlinearly increases with the electric...

The effect of the bulk Longitudinal-Optical (LO) phonon on the binding energy is investigated for a shallow donor impurity in a superlattice in the effective mass approximation by using the variational approach. The results are obtained as a function of parameters which characterize the superlattice and the position of the impurity center. The results show that the bulk Longitudinal-Optical (LO...

A rapidly-growing interest in WTe2 has been triggered by the giant magnetoresistance effect discovered in this unique system. While many efforts have been made towards uncovering the electron- and spin-relevant mechanisms, the role of lattice vibration remains poorly understood. Here, we study the coherent vibrational dynamics in WTe2 crystals by using ultrafast pump-probe spectroscopy. The osc...

Interwell optical-phonon-assisted transitions are studied in an asymmetric double-quantum-well heterostructure comprising one narrow and one wide coupled quantum wells (QW’s). We show that the depopulation rate of the lower subband states in the narrow QW can be significantly enhanced, thus facilitating the intersubband inverse population, if the depopulated subband is aligned with the second s...

The steady state hole transport properties of GaSb were investigated by the Ensemble Monte Carlo method (EMC). In our model we taken in to account heavy and light hole valence bands, and the following scattering mechanisms: inelastic acoustic phonon; polar optical phonon; nonpolar optical; ionized impurity. The theoretical calculations are compared with available experimental results for the Ga...

Fano resonances are features in absorption, scattering or transport spectra resulting from the interaction of discrete and continuum states. They have been observed in a variety of systems. Here, we report a many-body Fano resonance in bilayer graphene that is continuously tunable by means of electrical gating. Discrete phonons and continuous exciton (electron-hole pair) transitions are coupled...

The transient behavior of the optical susceptibility of polydiacetylene induced by an ultrafast pump field is investigated. Within a two-level model which includes phonon effects phenomenologically, an analytical expression for the nonlinear susceptibility is obtained. In addition to spectral hole burning, the novel phenomenon of optical nutation is found. Both this nutation and the shape of th...