A. A. Maksimov

Effects of disorder and isotopic substitution in the specific heat and Raman scattering in LuB12

Precision measurements of the specific heat and spectral intensity I(ω) of Raman scattering for LuNB12 single crystal samples with various boron isotopes (N = 10, 11, nat) have been performed at low and intermediate temperatures. A boson peak in the low-frequency part of the I(ω) spectrum has been observed for the first time for lutetium dodecaboride at liquid nitrogen temperatures. It has been shown that low-temperature anomalies in the specific heat, along with the features of Raman spectra, can be interpreted in terms of the transition to a cageglass state at T* = 50−70 K, which appears when Lu3+ ions are displaced from the centrosymmetric position in cavities of a rigid covalent boron sublattice towards the randomly located boron vacancies. The concentrations of various two-level systems that correspond to two types of vibrational clusters with correlation lengths of 12–15 and 18–22 Å, respectively, have been estimated. The vibrational density of states of LuB12 has been calculated from Raman spectra in the model of soft atomic potentials. An approach has been proposed to explain the dielectrization of the properties of the YbB12 compound at T < T*, as well as the features of the formation of magnetic structures in RB12 antiferromagnets (R = Tb, Dy, Ho, Er, Tm) and the suppression of superconductivity in LuB12.

Spin-lattice relaxation of mn ions in ZnMnSe/ZnBeSe quantum wells measured under pulsed photoexcitation

The dynamics of spin-lattice relaxation of the Mn ions in

Kinetics of radiative recombination in strongly excited ZnSe/BeTe superlattices with a type-II band alignment

(\mathrm{Zn},\mathrm{Mn})\mathrm{Se}

Giant blue shift of photoluminescence in strongly excited type-II ZnSe/BeTe superlattices

-based diluted-magnetic-semiconductor quantum wells is studied by time-resolved photoluminescence. The spin-lattice relaxation time varies by five orders of magnitude from

Interface properties and in-plane linear photoluminescence polarization in highly excited type-II ZnSe/BeTe heterostructures with equivalent and nonequivalent interfaces

{10}^{\ensuremath{-}3}

Picosecond carrier relaxation in type-II ZnSe/BeTe heterostructures

down to

Spin diffusion in the Mn 2 + ion system of II-VI diluted magnetic semiconductor heterostructures

{10}^{\ensuremath{-}8}\phantom{\rule{0.3em}{0ex}}\mathrm{s}

Raman scattering in ZrB12 cage glass

, when the Mn content increases from 0.4 up to 11%. Free carriers play an important role in this dynamics. Hot carriers with excess kinetic energy contribute to heating of the Mn system, while cooling of the Mn system occurs in the presence of cold background carriers provided by modulation doping. In a

Interface Properties and in-Plane Linear Photoluminescence Polarization in Highly Excited Type-II ZnSe/BeTe Heterostructures

{\mathrm{Zn}}_{0.89}{\mathrm{Mn}}_{0.11}\mathrm{Se}

Formation of metastable above-barrier hole states in ZnSe/BeTe type II heterostructures under high-density optical excitation

quantum well structure, where the spin-lattice relaxation process is considerably shorter than the characteristic lifetime of nonequilibrium phonons, also the phonon dynamics and its contribution to heating of the Mn system are investigated.