The status of lazurite as a valid mineral species has been confirmed. The neotype specimen from the Malaya Bystraya gem lazurite deposit, Baikal Lake area has been studied using electron microprobe, wet chemical analysis, ESR, IR, Raman, X-ray photoelectron spectroscopy, UV-Vis-near IR absorption and luminescence spectroscopy, and powder X-ray diffraction. The empirical formula of the neotype sample is (Na 6.97 Ca 0.88 K 0.10 ) 7.96 [Si 6.04 Al 5.96 ] 12 O 24 (SO 4 ) 1.09 ( S_3^∙ - ) 0.55 S_0.05^2 - Cl 0.04 ⋅0.72H 2 O, where S_3^∙ - is trisulfide radical anion, which is a blue chromophore. The idealized formula Na 7 Ca(Al 6 Si 6 O 24 )(SO 4 ) S_3^∙ - ⋅H 2 O has been approved by the IMA Commission on New Minerals, Nomenclature and Classification, proposal #20-H. The crystal structure of lazurite is characterized by commensurate and incommensurate modulations; the a parameter of the cubic sub-cell is 9.087(3) Å. The neotype sample is slightly birefringent, with α' = 1.523(2) and γ' = 1.525(2).

—The status of lazurite as a valid mineral species has been confirmed. The neotype specimen from the Malaya Bystraya gem lazurite deposit, Baikal Lake area has been studied using electron microprobe, wet chemical analysis, ESR, IR, Raman, X-ray photoelectron spectroscopy, UV-Vis-near IR absorption and luminescence spectroscopy, and powder X-ray diffraction. The empirical formula of the neotype sample is (Na 6.97 Ca 0.88 K 0.10 ) 7.96 [Si 6.04 Al 5.96 ] 12 O 24 (SO 4 ) 1.09 ( ) 0.55 Cl 0.04 ⋅0.72H 2 O, where is trisulfide radical anion, which is a blue chromophore. The idealized formula Na 7 Ca(Al 6 Si 6 O 24 )(SO 4 ) ⋅H 2 O has been approved by the IMA Commission on New Minerals, Nomenclature and Classification, proposal #20-H. The crystal structure of lazurite is characterized by commensurate and incommensurate modulations; the a parameter of the cubic sub-cell is 9.087(3) Å. The neotype sample is slightly birefringent, with α ' = 1.523(2) and γ ' = 1.525(2).

The status of lazurite as a valid mineral species has been confirmed. The neotype specimen from the Malaya Bystraya gem lazurite deposit, Baikal Lake area has been studied using electron microprobe, wet chemical analysis, ESR, IR, Raman, X-ray photoelectron spectroscopy, UV-Vis-near IR absorption and luminescence spectroscopy, and powder X-ray diffraction. The empirical formula of the neotype sample is (Na6.97Ca0.88K0.10)(7.96)[Si6.04Al5.96](12)O-24(SO4)(1.09)(S-3(center dot-))(0.55)S0.05-2Cl0.04 center dot 0.72H(2)O, where S-3(center dot-) is trisulfide radical anion, which is a blue chromophore. The idealized formula Na7Ca(Al6Si6O24)(SO4)S-3(center dot-)center dot H2O has been approved by the IMA Commission on New Minerals, Nomenclature and Classification, proposal #20-H. The crystal structure of lazurite is characterized by commensurate and incommensurate modulations; the a parameter of the cubic sub-cell is 9.087(3) angstrom. The neotype sample is slightly birefringent, with alpha' = 1.523(2) and gamma' = 1.525(2). \

We study and compare optical microcavities formed by GaN planar nanowires. Nanostructures with structural defects such as stacking faults and without defects are considered. The behavior of an exciton localized in a stacking fault is considered. Different behavior of the photoluminescence intensity and the photoluminescence decay time is observed for the cases under consideration. Theoretical calculations show the localization of the field at the ends of the structure.

The GaN planar hexagonal microcavities are grown by the selective vapor-phase epitaxy technique. The spectra are measured by the low-temperature cathodoluminescence method using a scanning electron microscope. The obtained spectra show a huge Rabi splitting (~100 meV). Numerical simulation of the spatial distribution of the intensities of modes in a hexagonal cavity is carried out. Certain modes can have a high spatial localization leading to strong coupling with the exciton and huge Rabi splitting. The fraction of excitons in polariton modes, which correlates with the intensity of exciton radiation associated with these modes, is theoretically calculated for hexagonal-shaped microcavities. Thus, the form of the dependence of the radiation probability on the eigenfrequencies of the structure is obtained.

The present paper presents new U–Pb and Sm–Nd age data obtained for granulites of the Cheremshanskaya Unit enclosing metamorphosed volcano-sedimentary sulfide ores, in which sulfur isotope mass-independent fractionation (MIF–S) was established. Zircons from orthotectites that cut hosted paragranulites yielded aconcordant U–Pb age of 1866.8 ± 7.6 Ma, reflecting the final stage of granulite metamorphism. The model age (ТND (DM)) of ~3.0 Ga obtained for graphite–sulfide–cordierite (±Bt) and garnet–biotite–orthopyroxene paragneisses indicates that the protolith of sedimentary rocks was formed in the Mesoarchaean. As evidenced from various sources, the Sm–Nd isotopic characteristics of orthotectites differ from those of paragneisses.

A significant difference in the growth mechanism of spatially closed structures of gallium nitride during selective growth in submicron windows with and without penetration into the GaN sublayer was demonstrated. The mechanisms of generation and development of dislocations, their role in the formation of self-organizing coaxial structures were modeled.

The effect of annealing temperature and time on the luminescence intensity of the InGaN/GaN heterostructure subjected to ion beam etching was studied. We show that annealing at a temperature of 1100°C makes it possible to eliminate the radiation defects in the GaN layers that arise in the etching process with a focused Ga+ ion beam (30 keV).

—We present results of study of sulfide ore occurrence in highly metamorphosed (granulite facies) Archean rocks of the Siberian craton basement. The host rocks and ore minerals are briefly described, and new data on the multiple sulfur isotope (δ33S, δ34S, Δ33S) composition of sulfides are presented. Application of high-resolution analytical methods enabling the assessment of the sulfur isotope behavior in situ made it possible to reveal mass-independent fractionation of sulfur isotopes in the rock samples. The isotopic composition of sulfur in the sulfides indicates its inflow from several sources, including the ancient Archean atmosphere, where primary sulfur has passed through a cycle of fractionation. Despite the high-gradient metamorphism, the subsequent ultrametamorphic and post-ultrametamorphic transformations accompanied by a change in the primary mineral composition of rocks and by chemogenic fractionation of sulfur, the signature of the sedimentary source of sulfur in sulfide ores has been well preserved. Analysis of the chemical composition of rocks and ore minerals and of sulfur isotopes has led to the conclusion that the studied rocks are metamorphosed Late Archean analogs of black shales and the sulfide mineralization is of stratiform pyrite type.

The effect of the growth temperature and the flow of trimethylgallium on the process of selective epitaxy of gallium nitride in windows of submicron size have been studied. The conditions under which homogeneous nucleation and coalescence of nuclei are combined with a low growth rate are determined. The steady growth of variously oriented gallium nitride strips with a height of 50 nm and a width of 600 nm was realized.

Проведено геохимическое изучение карбонатных пород раннедокембрийских и фанерозойских метаморфических комплексов и выявлены их различия. Докембрийские мраморы и кальцифиры изучены в Онотском зеленокаменном поясе, китойском и шарыжалгайском гранулитовых комплексах Присаянского и енисейской серии Ангаро-Канского выступов Сибирского кратона; беломорском и лапландском комплексах, Северо-Печенгской структуре, сортавальской свите Фенноскандинавского щита; ваханском комплексе Бадахшанского массива. Фанерозойские – в ольхонском, слюдянском, святоносском комплексах Прибайкалья, боксонской серии и иркутной свите Восточного Саяна, дербинском комплексе и алхадырской свите Присаянья, юдинской свите и Панимбинско-Рыбинском поясе Енисейского кряжа, музкольском комплексе Восточного Памира. Докембрийские карбонатные породы по сравнению с фанерозойскими обогащены Fe, Mn и обеднены Sr, Ba при близко низком уровне содержаний РЗЭ. В архее обогащение Fe, Mn протолитов мраморов и кальцифиров обусловлено доминированием основных и ультраосновных пород в питающих провинциях. В палеопротерозое по сравнению с фанерозоем доля Fe, Mn в карбонатных породах уменьшилась, а Al, K, Ba, Sr возросла за счет участия в формировании их протолитов гранитно-метаморфического слоя Земли. Распределение петрогенных и редких элементов в мраморах и кальцифирах определяется формами их нахождения: 1) в изоморфных рядах Ca–Mg карбонатов c примесью Fe, Mn, Ba, Sr, РЗЭ; 2) присутствием в мраморах минералов Na, K, Ba, Sr; 3) наличием тонких (в мраморах) и крупных (кальцифирах) фракций минералов с железом, Mn Al, Ti, Zr, Cr, V, Ni, S. По выполненным палеореконструкциям поведения РЗЭ в карбонатных породах в архее – раннем палеопротерозое доминировали интракратонные мелкие моря. Открытые океаны появились на рубеже 2–1,9 млрд лет, но широкое развитие карбонатные породы получили в мезо-неопротерозое и фанерозое. Выявленные особенности являются основой проведения возрастных палеореконструкций протолитов по петрогеохимическим характеристикам карбонатных пород докембрийских и фанерозойских метаморфических комплексов.

Our study describes FIB technological aspects of preparing mask for GaN selective area epitaxy on Si3N4/GaN template.

We present results of experiments concerning the loss of internal quantum efficiency of the GaAs/AlGaAs heterostructure due to the focused ion beam-induced radiation defects. Firstly we show that 300°C annealing in the high vacuum conditions leads to a partial recovery of the internal quantum efficiency and, therefore, photoluminescence regains some of its intensity. Secondly we show that 620°C annealing in the presence of As vapor leads up to 80% recovery of the internal quantum efficiency depending on the etching depth. Achieved results proves focused ion beam technique to be potent for the fabrication of photonic structures based on A3B5 materials containing active layer.

The effect of focused ion beam (FIB) etching by 30 keV Ga+ on photoluminescence of AlGaAs/GaAs heterostructure is studied. During etching process, high-energy ions induce radiation defects that lead to a decrease of heterostructure internal quantum efficiency of luminescence. We used the SRIM software to simulate the radiation defects penetration depths in AlGaAs/GaAs heterostructure, then carried out FIB etching guided by received information. Annealing of the structure at 300 °C showed partial recovery of the internal quantum efficiency. Subsequent annealing at 620 °C showed almost full recovery of quantum efficiency depending on the etching depth. Experimental findings allowed us to affirm that FIB etching with subsequent annealing is a potential tool for making photonic nanodevices.

In the Si3N4 layer, coaxial and single submicrometer GaN structures of hexagonal shape with pyramidal facets are formed by selective vapor-phase epitaxy in windows produced with a focused ion beam. It is found that coaxial hexagonal structures are formed during the growth process in ring-shaped mask windows.

The focused ion beam (FIB) is a potential tool in manufacturing microcircuit devices. The main downside of FIB etching process is radiation defects formation. To recover etching surface, we provide 300 C and 620 C annealing. Amount of radiation damage was determined by photoluminescence (PL) measurements.

The selective epitaxial growth of GaN by metalorganic vapor-phase epitaxy combined with ion-beam etching is investigated. To this end, partially masked GaN epitaxial layers are fabricated by depositing a thin Si3N4 layer onto the surface in a single technological process with the growth of GaN and the subsequent opening of windows of different shapes in this layer by an ion beam. Selective epitaxial growth regimes are studied. It is shown that, in a situation where the total area of the windows in the mask is small relative to the total area of the sample, the required epitaxy duration should be 5–10 s, which impairs the reproducibility of the parameters of the epitaxial process. It is also shown that the mechanism of the selective growth of submicrometer objects differs significantly from that for planar layers and selectively grown layers with dimensions of ~1 μm or greater. The effect of precursor (trimethylgallium and ammonia) fluxes on the character of selective epitaxy is examined. To investigate the possibilities of varying mask topology for fabricating model objects with regard to photonic crystals, the impact of the shape and orientation of the windows in the Si3N4 mask on the character of selective epitaxy is studied.

Authors represent utilizing UHV Ga FIB for preparing a Si3N4/GaN substrate for submicron selective-area epitaxy. In result, GaN submicron stripes were grown in the 100, 200 and 500 nm windows of a Si3N4 mask layer. SEM investigations show good crystalline perfection of the grown stripes.