Search results for "Band structure"
showing 10 items of 215 documents
PbS Nanodots Embedded in ZrO2 Thin Films for Ultraviolet Radiation Dosimetry
2011
PbS nanodots embedded in ZrO2 thin film matrix (ZrO2:PbS films) were investigated for UV radiation dosimetry purposes. ZrO2:PbS films were UV irradiated using wavelengths 250 - 400 nm. Photoelectron emission spectra of ZrO2:PbS films were recorded and band structure of the films was calculated. It was found that density of localized states increased with increase in concentration of PbS nanodots which allowed to suggest that PbS nanodots are responsible for creation of localized states. Number of localized states decreased after UV irradiation. The linear correlation between number of localized states and time of UV exposure was observed. Observed changes in band structure of ZrO2:PbS films…
Brief Review of the Effects of Pressure on Wolframite-Type Oxides
2018
In this article we review the advances that have been made on the understanding of the high-pressure structural, vibrational, and electronic properties of wolframite-type oxides since the first works in the early 1990s. Mainly tungstates, which are the best known wolframites, but also tantalates and niobates, with an isomorphic ambient-pressure wolframite structure, have been included in this review. Apart from estimating the bulk moduli of all known wolframites; the cation-oxygen bond distances and their change with pressure have been correlated with their compressibility. The composition variations of all wolframites have been employed to understand their different structural phase transi…
A Brief Review of the Effects of Pressure on Wolframite-Type Oxides
2018
In this article, we review the advances that have been made on the understanding of the high-pressure (HP) structural, vibrational, and electronic properties of wolframite-type oxides since the first works in the early 1990s. Mainly tungstates, which are the best known wolframites, but also tantalates and niobates, with an isomorphic ambient-pressure wolframite structure, have been included in this review. Apart from estimating the bulk moduli of all known wolframites, the cation–oxygen bond distances and their change with pressure have been correlated with their compressibility. The composition variations of all wolframites have been employed to understand their different structural phase …
Narrow Band Solid-Liquid Composite Arrangements: Alternative Solutions for Phononic Crystal-Based Liquid Sensors
2019
Periodic elastic composite structures attract great attention. They offer the ability to design artificial properties to advance the control over the propagation of elastic/acoustic waves. In previous work, we drew attention to composite periodic structures comprising liquids. It was shown that the transmission spectrum of the structure, specifically a well-isolated peak, follows the material properties of liquid constituent in a distinct manner. This idea was realized in several liquid sensor concepts that launched the field of phononic crystal liquid sensors. In this work we introduce a novel concept&mdash
Electronic structure of indium selenide probed by magnetoabsorption spectroscopy under high pressure
2010
We report on an investigation of the peculiar electronic structure of the layered semiconductor InSe by magneto-optical experiments under high pressure up to 5 GPa. Magneto-absorption spectroscopy is performed under pulsed magnetic field up to 53 T using a specific setup. Excitonic magnetofingerprints and high-field oscillatory magnetoabsorption yield significant details on the band structure. In addition, the application of an external pressure unveils phenomena that confirm the specific $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ model proposed for this compound on the basis of earlier measurements.
Ab-Initio Calculations of Oxygen Vacancy in Ga2O3 Crystals
2021
The research has been funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08856540). J. Purans and A.I.Popov acknowledge the ERAF project 1.1.1.1/20/A/057 “Functional Ultrawide Bandgap Gallium Oxide and Zinc Gallate Thin Films and Novel Deposition Technologies”. The Institute of Solid State Physics, University of Latvia (Latvia) as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD01-2016-2017-Teaming Phase2 under grant agreement No. 739508, project CAMART2.
Yodatos bajo condiciones extremas: Transiciones de fase inducidas por la presión, propiedades estructurales, vibracionales y electrónicas
2022
La estructura cristalina de los yodatos metálicos juega un papel importante en la respuesta SHG, así como también lo hacen la estructura de bandas electrónica y la energía de bandgap de la misma. Por ello, en esta tesis doctoral se estudia en profundidad y se presentan y analizan resultados de la estructura cristalina a alta presión, las vibraciones atómicas y la estructura de bandas electrónica de cuatro yodatos metálicos. Estos son el yodato de hierro, Fe(IO3)3, el yodato de cobalto, Co(IO3)2, el yodato de zinc, Zn(IO3)2, y yodato de magnesio Mg(IO3)2. Estos materiales han sido estudiados por medio de difracción de rayos X a alta presión (HPXRD), dispersión Raman a alta presión (HPRS), es…
Ferromagnetic ordering in GdPdCd
2010
Abstract GdPdCd was obtained in pure form via reaction of the elements in a sealed tantalum tube in a high-frequency furnace. The structure was investigated by X-ray diffraction on both powders and single crystals: ZrNiAl type, P 6 2m , a=758.2(1), c=391.78(7) pm, wR2=0.0410 for 358 F2 values and 14 variables. Striking structural motifs of GdPdCd are two types of palladium-centered tricapped trigonal prisms [Pd1Cd3Gd6] and [Pd2Cd6Gd3]. Together the palladium and cadmium atoms build a three-dimensional network in which the gadolinium atoms fill distorted pentagonal channels. Susceptibility measurements reveal Curie–Weiss behaviour with an effective magnetic moment of 8.2(1) μB/Gd. GdPdCd ord…
Density-functional tight-binding modeling of electromechanics of phosphorene
2018
Single-layer black phosphorus or phosphorene is a two-dimensional material made from a puckered honeycomb structure. It is a semiconductor with a tunable band gap and both its mechanical and electronic properties are highly asymmetric because of the puckering. Recently there has been numerous computational studies and some experimental works trying to bring deeper understanding about this relatively new 2D material. In this study we simulate phosphorene using computationally low-cost density functional tight-binding (DFTB) method to see how stretching, shearing and bending affect its electronic properties. The band structure analysis shows that there is a relation between shearing and bendi…
A chiral molecular conductor: synthesis, structure, and physical properties of [ET]3[Sb2(L-tart)2].CH3CN (ET = bis(ethylendithio)tetrathiafulvalene; …
2004
The salt [ET](3)[Sb(2)(L-tart)(2)].CH(3)CN (1) has been obtained by electrocrystallization of the organic donor bis(ethylendithio)tetrathiafulvalene (ET or BEDT-TTF) in the presence of the chiral anionic complex [Sb(2)(L-tart)(2)](2-) (L-tart = (2R,3R)-(+)-tartrate). This salt crystallizes in the chiral space group P2(1)2(1)2(1) (a = 11.145(2) angstroms, b = 12.848(2) angstroms, c = 40.159(14) angstroms, V = 5750.4(14) angstroms(3), Z = 4) and is formed by alternating layers of the anions and of the organic radicals in a noncentrosymmetric alpha-type packing. This compound shows a room temperature electrical conductivity of approximately 1 S.cm(-1) and semiconducting behavior with an activa…