First-principles investigation of structural, electronic, optical and dynamical properties in CsAu

Erdinç, Bahattin; Soyalp, F.; Akkuş, Harun

doi:10.2478/s11534-011-0036-1

Cited by 6 publications

(4 citation statements)

References 29 publications

(39 reference statements)

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“…Phonon spectra of CsAu calculated by DFPT showing the LO (orange) and TO (blue) phonon branches, with the remaining branches (one optical and three acoustic) in black. This is in agreement with the previous reported phonon spectra …”

Section: Resultssupporting

confidence: 94%

“…Although KAu is believed to exist at high pressures, the structural optimization from the related structures provides accurate lattice parameters and properties for comparison here. The cubic lattice constants for all three systems, which are the only free structural parameters in a CsCl-type structure, were optimized using an 8 × 8 × 8 Monkhorst–Pack k mesh and a cutoff energy of 550 eV. ,− The effect of spin–orbit interaction (SOI) on determination of the structural stability was also examined. The total energies of the CsCl-type structure and the Cmcm -type structure were calculated using the complete SOI implementation in VASP.…”

Section: Computational Detailsmentioning

confidence: 99%

See 1 more Smart Citation

On the Stereochemical Inertness of the Auride Lone Pair: Ab Initio Studies of AAu (A = K, Rb, Cs)

Miao

Brgoch²,

Krishnapriyan³

et al. 2013

Inorg. Chem.

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The "lone" 6s electron pair often plays a key role in determining the structure and physical properties of compounds containing sixth-row elements in their lower oxidation states: Tl(+), Pb(2+), and Bi(3+) with the [Xe]4f(14)5d(10)6s(2) electronic configuration. The lone pairs on these ions are associated with reduced structural symmetries, including ferroelectric instabilities and other important phenomena. Here we consider the isoelectronic auride Au(-) ion with the [Xe]4f(14)5d(10)6s(2) electronic configuration. Ab initio density functional theory methods are employed to probe the effect of the 6s lone pair in alkali-metal aurides (KAu, RbAu, and CsAu) with the CsCl structure. The dielectric constants, Born effective charges, and structural instabilities suggest that the 6s lone pair on the Au(-) anion is stereochemically inert to minor mechanical and electrical perturbation. Pressures greater than 14 GPa, however, lead to reorganization of the electronic structure of CsAu and activate lone-pair involvement and Au-Au interactions in bonding, resulting in a transformation from the cubic CsCl structure type to an orthorhombic Cmcm structure featuring zigzag Au-Au chains.

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Section: Resultssupporting

confidence: 94%

Section: Computational Detailsmentioning

confidence: 99%

On the Stereochemical Inertness of the Auride Lone Pair: Ab Initio Studies of AAu (A = K, Rb, Cs)

Miao

Brgoch²,

Krishnapriyan³

et al. 2013

Inorg. Chem.

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“…It is known that the Cs and Au atoms form an ionic crystal in the CsCl-type structure. The CsAu shows an optical bandgap of 2.6 eV that was extracted from the photoemission spectroscopy experiments [30] and an indirect bandgap of 0.9 eV (from the point X to R in the Brillouin zone) that was predicted by DFT calcula-tions [31,32]. The MD simulations have predicted that the liquid CsAu has a frequency gap between the longitudinal and transverse optical branches in the limit of long wavelength, also showing a non-metallic character [33].…”

Section: Csaumentioning

confidence: 94%

Two-dimensional ionic crystals: The cases of IA-VII alkali halides and IA-IB CsAu

Ono¹

2022

Preprint

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The alkali halides, known as ionic crystals, have the NaCl-type or CsCl-type structure as the ground state. We study the structural, vibrational, and electronic properties of two-dimensional (2D) ionic crystals from first-principles. Two potential structures that are hexagonal and tetragonal are investigated as structural templates. Through phonon dispersion calculations, 8 and 16 out of 20 alkali halides in the hexagonal and tetragonal structures are dynamically stable, respectively. The electron energy gaps range from 6.8 eV for LiF to 3.9 eV for RbI and CsI in the tetragonal structure within the generalized gradient approximation. By considering the Madelung energy and the core-core repulsion, we propose a hard sphere model that accounts for the nearest-neighbor bond length and the cohesive energy of 2D alkali halides. The 2D CsAu in the tetragonal structure is also predicted to be stable as an ionic crystal including only metallic elements, showing a band gap of 2.6 eV that is higher than that of the 3D counterparts.

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“…The trends of electronic properties of AAu in the B2 (CsCl-type) structure (A = Li, Na, K, Rb, and Cs) are interesting because the LiAu, NaAu, and KAu are metal, whereas the RbAu and CsAu are semiconductor [3]. The optical bandgap of CsAu was reported to be 2.6 eV [3], while the indirect bandgap was predicted to be 0.3 eV for RbAu [4] and about 1.0 eV for CsAu [5,6] within the density-functional theory (DFT) calculations. The molecular dynamics simulations have predicted that the liquid CsAu has a frequency gap between the longitudinal optical (LO) and transverse optical (TO) branches in the limit of long wavelength, also showing a non-metallic character [7].…”

mentioning

confidence: 99%

Hypothetical FrAu: An outlier in the B2 compounds

Ono

2021

Preprint

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The ordered alloys of alkali metals (Rb and Cs) and gold (Au) have the B2 (CsCl-type) structure and show a semiconducting property, irrespective to the metallic constituents. Francium (Fr) is classed as an alkali metal and is expected to form the B2 structure with Au. However, it is difficult to synthesize such a compound experimentally due to a half-life of a few ten minutes in the Fr atom. In this paper, by using the first-principles method, we study the structural and electronic properties of FrAu in the B2 structure. The FrAu has a relatively large lattice constant and a relatively small bulk modulus among 310 B2 compounds. The profiles of the electron and phonon band structures of the FrAu are quite similar to those of the CsAu. We predict that the FrAu is included to one of the ionic compounds as well as the RbAu and CsAu.

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First-principles investigation of structural, electronic, optical and dynamical properties in CsAu

Cited by 6 publications

References 29 publications

On the Stereochemical Inertness of the Auride Lone Pair: Ab Initio Studies of AAu (A = K, Rb, Cs)

On the Stereochemical Inertness of the Auride Lone Pair: Ab Initio Studies of AAu (A = K, Rb, Cs)

Two-dimensional ionic crystals: The cases of IA-VII alkali halides and IA-IB CsAu

Hypothetical FrAu: An outlier in the B2 compounds

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