Оптические свойства и электронные характеристики празеодима и неодима в конденсированном состоянии

The optical properties of unoxidized surfaces of polycrystalline Pr and Nd films in the spectral range 0.4 - 2.6 μm are studied. Optical constants were measured by Beattie ellipsometric method. Dispersion dependences of the optical conductivity σ, the reflectivity R, imaginary and real parts of the dielectric constant ε1 and ε2, and the function of characteristic electron energy losses Im (ε) -1 were calculated using the obtained optical constants. The paper presents the optical properties of both films and liquid metals studied earlier. The electronic characteristics of praseodymium and neodymium in solid thin-film and liquid states are calculated using the results of measurements in the infrared region of the spectrum using the two-band conductivity model.

Эллипсометрия нанокристаллических пленок VO-=SUB=-2-=/SUB=-, VO-=SUB=-2-=/SUB=- : Mg, VO-=SUB=-2-=/SUB=- : Ge

The spectra of the refractive index n(λ) and the extinction coefficient k(λ) of thin VO2, VO2: Mg, VO2:Ge films were measured using the ellipsometric method. For an undoped VO2 film at a wavelength λ = 632.8 nm, near the insulator-metal phase transition, the n(T) and k(T) thermal hysteresis loops were studied. An interpretation of the results is given on the base of the Moss relation, the idea of a change in n(T) and k(T) with an impurity variation of the material density, and also on the base of the ideology of the Coulomb transformation of the density of states function in strongly correlated materials.

Особенности спектров оптического поглощения интерметаллических соединений GdFe-=SUB=-2-=/SUB=- и LuFe-=SUB=-2-=/SUB=-

The optical properties of binary GdFe_2 and LuFe_2 compounds are studied by the ellipsometric method in the 0.22–17 μm spectral range. A number of spectral and electronic characteristics are determined. The experimental dependences of optical conductivity in the light quantum absorption region are interpreted based on previously published calculations of electronic states densities.

Определение профиля состава квантовых ям HgTe/Cd-=SUB=-x-=/SUB=-Hg-=SUB=-1-x-=/SUB=-Te методом одноволновой эллипсометрии

An ellipsometric method for reconstruction of the composition profile throughout the thickness in thin mercury-cadmium-telluride nanostructures grown by MBE has been developed. The method is based on ellipsometric data, measured during structure growth and following solution of the inverse ellipsometric problem. For this, a replacement of a part of the inhomogeneous layer by a homogeneous substrate with specially chosen optical constants has been done. Numerical simulation showed the correctness of such replacement and the efficiency of the developed algorithm. Using this method, the active region of the heterostructure consisting of five HgTe quantum wells separated by wide-band CdHgTe spacers has been studied. Using the results of continuous measurements of ellipsometric parameters obtained in situ during structure growth, the composition profiles for all five sequentially grown quantum wells was determined. A high repeatability of the composition distribution through the thickness is shown.

Структура электронных состояний в FeSb-=SUB=-2-=/SUB=- по данным оптической спектроскопии и зонных расчетов

The electronic structure and optical properties of the binary intermetallic compound FeSb2 have been studied. The band structure was calculated in the local density approximation, which showed the existence of a narrow ~0.3 eV gap in the energy spectrum of this material. The spectral characteristics were studied by ellipsometric method in the wavelength range of 0.22-18 μm. It is shown that the experimental optical conductivity of the compound in the region of interband transitions is satisfactorily interpreted in the framework of the calculations of the density of electronic states. The work was performed as part of the state assignment of the Ministry of Education and Science of the Russian Federation (theme Electron, N AAAA-A18-118020190098-5) with partial support from the Russian Foundation for Basic Research (project N 17-52-45056).