Electronic band structure and inter-atomic bonding in tetragonal BiOCuS as a parent phase for novel layered superconductors

Abstract

A B S T R A C TVery recently, the tetragonal BiOCuS was synthesized and declared as a new superconducting system with Fe-oxypnictide -related structure. Here, based on first-principle FLAPW-GGA calculations, the structural parameters, electronic bands picture, density of states and electron density distribution for BiOCuS are investigated for the first time. Our results show that, as distinct from related metallic-like FeAs systems, BiOCuS phase behaves as an ionic semiconductor with the calculated indirect band gap at about 0.48 eV. The superconductivity for BiOCuS may be achieved exclusively by doping of this phase. Our preliminary results demonstrate that as a result of hole doping, the [CuS] blocks become conducting owing to mixed Cu 3d + S 3p bands located near the Fermi level. For the hole doped BiOCuS the Fermi surface adopts a quasi-two-dimensional character, similarly to FeAs SCs.

Competition between electron-phonon coupling and spin fluctuations in superconducting hole-doped CuBiSO

“…9 The generalized-gradient approximation (GGA) band structure and partial electronic density of states (DOS) are shown in Fig. 1; in agreement with previous calculations, 5,8,15 we find that the stoichiometric compound is a semiconductor 5,6 with an indirect gap of ∆ ≈ 0.5 eV (GGA); the top of the valence band occurs along the Γ − M line, and we choose it as the zero of the energy in the following. The electronic structure in an energy range ∼ 7 eV below the top of the valence band in BiO-CuS is derived from Cu d and S p states (see top panel of Fig.…”

Structural, elastic, electronic properties and stability trends of 1111-like silicide arsenides and germanide arsenides MCuXAs (M=Ti, Zr, Hf; X=Si, Ge) from first principles

“…In Fig. 2, the "structure map" (c/a versus q) is depicted for 19 various 1111-like phases calculated by us [34][35][36][37][38] within the same FLAPW method, which include the representatives of the aforementioned groups of materials such as LnFePnO, LnZnPnO, and LnCuChO. We see that these phases are divided into three separate Table 1 The optimized lattice parameters (a and c, inÁ) and internal coordinates (zM, z As ) for six 1111-like silicide arsenides and germanide arsenides MCuXAs (M = Ti, Zr, Hf; X = Si and Ge).…”

“…2. Structure map for various quaternary tetragonal ZrCuSiAs-type phases as obtained from optimized structural data within FLAPW calculations [34][35][36][37][38]. Inset: valence densities for LaAgSeO and ZrCuSiAs are depicted to illustrate 2D-and 3D-like types of inter-atomic bonding in I, II versus III groups of these phases, see also text.…”

Investigation of Electronic and Optical Properties of Novel Oxychalcogenides by Density Functional Theory

“…The rare earth coinage-metal chalconegides are interesting to researchers because of the greater structural complexity due to the additional anion which allows concomitant affect on the electronic structure and their properties [1][2][3][4]. These unique physical chemistry properties have driven tremendous applications for diverse areas such as transparent conductors and materials for rechargeable battery [5] as well as materials for unusual magnetic, chemical and optoelectronic properties [6,7]. The rare earth coinage-metal chalconegides, LnMOCh (Ln = rare earth element; M = Cu, Ag; Ch = S, Se, Te) are a class of layered materials that consist of alternating [Ln 2 O 2 ] 2+ oxide layers and [M 2 Ch 2 ] 2chalcogenide layers stacked perpendicular to the c-axis in a tetragonal unit cell [7][8][9].…”