Electronic structure of the high-temperature tetragonal Tl3PbBr5 phase

Denysyuk, N.M.; Bekenev, V.L.; Karpets, M. V.; Parasyuk, O.V.; Danylchuk, S.P.; Khyzhun, O.Y.

doi:10.1016/j.jallcom.2013.04.162

Cited by 30 publications

(9 citation statements)

References 22 publications

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“…It is worth mentioning that theoretical band-structure calculations of thallium lead bromide and chloride with the common formula Tl 3 PbX 5 (X = Cl, Br) have also revealed the existence of indirect gaps in these materials. 25,26 Such a good agreement between the GGA/LDA calculated band gaps with the experimental data is a clear indication of the presence of some defects within the host band gap, which effectively produce a red shift of the host absorption. The calculated band structure is very dense with respect to energy and contains many electron states.…”

Section: Resultsmentioning

confidence: 60%

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material

Brik

Kityk

Denysyuk

et al. 2014

Phys. Chem. Chem. Phys.

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A novel Tl3PbI5 crystal has been studied both experimentally and theoretically. Complex measurements of the X-ray photoelectron core-level and valence-band spectra for the pristine and Ar(+)-ion irradiated surfaces of a Tl3PbI5 single crystal grown by the Bridgman-Stockbarger method were performed in order to clarify their principal properties (charge carriers mobility, effective inter-band distances, effective absorption etc.) relevant for optoelectronic applications. The principal role of two heavy cations - Tl and Pb - is explored. The X-ray photoelectron spectroscopy results reveal a high chemical stability of the Tl3PbI5 single crystal surface which makes it very promising for technological applications. Theoretical band-structure calculations for the Tl3PbI5 compound reveal that the I 5p states dominate in the top of the valence band and play a crucial role in the formation of the optical features and charge carrier mobility. The bottom of the Tl3PbI5 valence band is formed mainly by the admixture of Tl 6s and Pb 6s states, while the unoccupied Pb 6p and Tl 6p states dominate at the bottom of the conduction band. The band energy dispersion related to effective masses and the charge carrier mobility is studied in detail. Crucially, the theoretical calculations reveal an indirect band gap for Tl3PbI5, which indicates a strong influence of the electron-phonon interaction on the observed optoelectronic features. The temperature measurements of the fundamental absorption have shown that the band energy gap of Tl3PbI5 increases from 2.29 to 2.39 eV when the temperature changes from 300 to 100 K.

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Section: Resultsmentioning

confidence: 60%

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material

Brik

Kityk

Denysyuk

et al. 2014

Phys. Chem. Chem. Phys.

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“…It should be emphasized that Tl and Hg atoms are considered to be heavy elements. 37,38 Therefore, in the present DFT calculations within the MBJ+U potential, 24,27 SOC 39−41 has been accounted for as well (we refer to these calculations, for clarity, as MBJ+U+SO). It is reported that consideration of the SOC approach for the first-principles band-structure calculations of heavy-element-bearing compounds (e.g., U, Np, Pu, Am, Th, etc.)…”

Section: ■ Methods Of Calculationsmentioning

confidence: 99%

Manifestation of Anomalous Weak Space-Charge-Density Acentricity for a Tl₄HgBr₆Single Crystal

Lavrentyev

Gabrelian

et al. 2016

Inorg. Chem.

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Density functional theory (DFT) calculations within the concept of the MBJ+U+SO (modified Becke-Johnson potential + U + spin orbit) approach were performed for a TlHgBr single crystal for the first time assuming weak noncentrosymmetry (space group P4nc). Excellent agreement was achieved between the calculated and experimental band-gap-energy magnitudes as well as the density of electronic states measured by the X-ray photoelectron spectroscopy method. It is a very principal result because usually the DFT calculations underestimate the energy-gap values. In the present study, we carry out calculations of the optical properties (absorption coefficient, real and imaginary parts of the dielectric function, electron energy-loss spectrum, refractive index, extinction coefficient, and optical reflectivity dispersions). It has been established that the principal origin of the observed weak acentricity is determined by delocalized band states at the top of the valence band originating from the p states of the Br atoms.

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“…The next most promising candidate, tetragonal Tl 3 PbBr 5 , has a very large (101) but possesses a relatively smaller band gap (2.9 eV) and is computed to be thermodynamically metastable at 0K (E hd = 16 meV per atom) according to the data obtained from the OQMD. Tl 3 PbBr 5 is also reported in literature to have been experimentally synthesized [62,63,64], without any mention of its dielectric properties.…”

Section: New Dielectric Materialsmentioning

confidence: 99%

Identification of High-Dielectric Constant Compounds from Statistical Design

Gopakumar,

Pal,

Wolverton

2022

Preprint

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The discovery of high-dielectric materials is crucial to increasing the efficiency of electronic devices and batteries. Here, we report three previously unexplored materials with very high dielectric constants (69 < < 101) and large band gaps (2.9< Eg(eV) < 5.5) obtained by screening materials databases using statistical optimization algorithms aided by artificial neural networks (ANN). Two of these new dielectrics are mixed-anion compounds (Eu5SiCl6O4 and HoClO), and are shown to be thermodynamically stable against common semiconductors via phase-diagram analysis. We also uncovered four other materials with relatively large dielectric constants (20< <40) and band gaps (2.3

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Electronic structure of the high-temperature tetragonal Tl3PbBr5 phase

Cited by 30 publications

References 22 publications

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material

Manifestation of Anomalous Weak Space-Charge-Density Acentricity for a Tl₄HgBr₆Single Crystal

Identification of High-Dielectric Constant Compounds from Statistical Design

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Electronic structure of the high-temperature tetragonal Tl3PbBr5 phase

Cited by 30 publications

References 22 publications

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material

Manifestation of Anomalous Weak Space-Charge-Density Acentricity for a Tl4HgBr6Single Crystal

Identification of High-Dielectric Constant Compounds from Statistical Design

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Manifestation of Anomalous Weak Space-Charge-Density Acentricity for a Tl₄HgBr₆Single Crystal