Electronic structure of oxygen-containing bismuth compounds

Based on the full potential linear muffin-tin orbitals (FPLMTO) calculation within density functional theory, we systematically investigate the electronic and optical properties of (100) and (110)-oriented (InN)/(GaN)n zinc-blende superlattice with one InN monolayer and with different numbers of GaN monolayers. Specifically, the electronic band structure calculations and their related features, like the absorption coefficient and refractive index of these systems are computed over a wide photon energy scale up to 20 eV. The effect of periodicity layer numbers n on the band gaps and the optical activity of (InN)/(GaN)n SLs in the both growth axis (001) and (110) are examined and compared. Because of prospective optical aspects of (InN)/(GaN)n such as light-emitting applications, this theoretical study can help the experimental measurements.

High pressure phase transition and band structures of different phases in CeO 2

New CrAs-based layered mixed-anion compounds Sr2ScCrAsO3 (SrScO-21113) and Ba3Sc2Cr2As2O5 (BaScO-32225) were synthesized, and their electronic structures and physical properties were investigated. The structures of these compounds comprise stacking of the anti-fluorite CrAs layer and perovskite-like SrScO or BaScO layers. The lattice constants of these compounds are relatively longer than those of the related compounds, such as BaCr2As2, owing to the insertion of a large perovskite blocking layer of SrScO/BaScO. While there are variations in the crystal structure of this system, such as 21113 and 32225, their chemical stability calculated by the first-principles calculations indicated that SrScO-21113 is energetically favorable compared to SrScO-32225. The formation energies of BaScO-32225 and BaScO-21113 are close to each other; in the experiment, while there was an indication of BaScO-21113 formation, only BaScO-32225 was formed as a single phase because of the low chemical stability of BaScO-21113. The partial density of states indicates that the majority of states are obtained from the 3d4-electrons of the Cr element hybridized modestly with p electrons at the Fermi energy. The magnetic properties of these compounds were paramagnetic, and they were different from related compounds, such as BaCr2As2, probably because of their long a-axis lengths. The temperature dependences of the electrical resistivities of both samples were in good agreement with the electronic band structure calculations. The variety of structures in the series of compounds with a CrAs layer results in different physical properties, and further development of new compounds may bring novel functionalities, such as superconductivity.

The electronic structures and magnetic properties are reported for ordered and disorderedSr2CrMoO6 presenting oxygen vacancies or/and antisite defects (ASs). We investigate the stability ofan antiparallel (AP) magnetic moment on Cr antisites and the calculations show that thesesolutions are more stable relative to the parallel solution for AS defects with or withoutoxygen vacancies. Electronic band structure calculations indicate that the perfectSr2CrMoO6 is half-metallic, and the half-metallic character is preserved forSr2CrMoO6 containing only oxygen vacancies, while the half-metallic nature is destroyed when25% ASs (50% ASs) with or without oxygen vacancies is present. For 25% ASswith two oxygen vacancies, the system possibly shows nonmetallic behavior. Theexperimentally observed reduction of the magnetic moment mainly arises from anantiferromagnetic coupling of Cr–O–Cr (Cr–Cr) bonds in a disordered sample.

Electronic structure of the heavy fermion superconductor Ce2PdIn8: Experiment and calculations

Electronic band structure calculations on thin films of the L21 full Heusler alloys X2YSi (X, Y = Mn, Fe, and Co): Toward spintronic materials

Crystal structure, electronic structure and thermoelectric properties of Cu 4Sn 7S 16

Relativistic electronic structure and Fermi surface of URu 2Si 2 in antiferromagnetic state

Atomic structure of O/Ir(2 1 0) nanofacets

The electronic structure of the quasi two-dimensional (2D) organic superconductor \(\)-(ET)2SF5CH2CF2SO3 was examined by measuring Shubnikov-de Haas (SdH) and angle-dependent magnetoresistance (AMRO) oscillations and by comparing with electronic band-structure calculations. The SdH oscillation frequencies follow the \(\) angular dependence expected for a 2D Fermi surface (FS), and the observed fundamental frequency shows that the 2D FS is 5% of the first Brillouin zone in size. The AMRO data indicate that the shape of the 2D FS is significantly non-circular. The calculated electronic structure has a 2D FS in general agreement with experiment. From the temperature and angular dependence of the SdH amplitude, the cyclotron and band effective masses were estimated to be \(\) and \(\),where g is the conduction electron g factor and \(\) the free electron mass. The band effective mass is estimated to be \(\) from the calculated electronic band structure.

CALCULATIONS OF THE SUPERCONDUCTING AND TRANSPORT PROPERTIES OF A15 STRUCTURE COMPOUNDS

Effects of crystal and electronic structures of ANb 2O 6 (A=Ca, Sr, Ba) metaniobate compounds on their photocatalytic H 2 evolution from pure water

Ab initio calculations were systematically investigated for nonmagnetic (NM), ferromagnetic (FM), and antiferromagnetic (AFM) states of new full-Heusler alloy Cr2MnSi in Hg2CuTi and Cu2MnAl-type structures. The calculations are based on the density functional theory, with the full potential linear muffin-tin orbital (FP-LMTO) method. The results show that the ferromagnetic Hg2CuTi prototype structure is the most stable. The optimized lattice parameter is found to be 5.643 A, with the total magnetic moment 0.30 μB. The electronic band structure calculations revealed that Cr2MnSi exhibits a metallic ferromagnet behavior. Using the Mehl method, we have also calculated the elastic constants and their related parameters such as Poisson’s ratio, Young modulus, Zener anisotropy, shear modulus, Kleinman parameter ξ, Lame constants (λ, μ), Cauchy pressure Pc, microhardness parameter, and the melting temperature Tm. Our calculation validates the conditions of mechanical stability in the cubic crystal. The estimation of the Curie temperature shows that the Cr2MnSi compound is a good candidate for the spintronic application.

For pt. IV see abstr. A71927 of 1970. The scheme for the rapid, approximate, calculation of transition metal band structures, recently developed by Hubbard (1969), has been extended to yield the electronic wavefunctions. As an illustration numerical results for the s, p and d character of the wavefunctions on the surface of the muffin tin sphere are presented for copper and body centred cubic iron.

A feasible strategy to realize the Majorana fermions is searching for a simple compound with both bulk superconductivity and Dirac surface states. In this paper, we performed calculations of electronic band structure, the Fermi surface and surface states, as well as measured the resistivity, magnetization, specific heat for TlSb compound with a CsCl-type structure. The band structure calculations show that TlSb is a Dirac semimetal when spin-orbit coupling is taken into account. Meanwhile, we first found that TlSb is a type-II superconductor with $T_c$ = 4.38 K, $H_{c1}$(0) = 148 Oe, $H_{c2}$(0) = 1.12 T and $\kappa_{GL}$ = 10.6, and confirmed it to be a moderately coupled s-wave superconductor. Although we can not determine which bands near the Fermi level $E_F$ to be responsible for superconductivity, its coexistence with the topological surface states implies that TlSb compound may be a simple material platform to realize the fault-tolerant quantum computations.