A first-principles study of electronic, optical and thermoelectric properties of TlXF₃ (X: Zn, Sr) perovskite crystal structure

Abstract

This study communicates the structural, electronic, optical, and thermoelectric properties of a perovskite TlXF3 (X: Zn, Sr) crystal structure using first-principles calculations. Both compounds were found structurally as well as thermodynamically stable in cubic phase. The bandgaps of both compounds belong to insulating region. The TlSrF3 exhibits direct bandgap of 4.37 eV at X symmetry point while TlZnF3 possess indirect bandgap of 3.95 eV (M-X). Using HSE functional, the calculated electronic bandgaps of TlSrF3 and TlZnF3 are 5.74 eV(X-X) and 5.36 eV (M-X), respectively. The analysis of electronic states in band structur shows that for TlSrF3, the top of valence band is composed of the F-p states whereas the states in lower potion of conduction band are impacted by the significant contribution of Tl-p orbital states. In case of TlZnF3, the states near the valence band maxima and conduction band minima are coming mainly form Tl atom. The dependence of thermoelectric properties such as electrical conductivity, Seebeck coefficient, Power factor, electronic thermal conductivity (κ) and Figure-of-merit (ZT) as a function of carrier concertation and temperature are investigated. The optical properties were also studied to understand the response of TlXF3 to incident photons of energies upto 14 eV. We conclude that the TlXF3 are promising candidates for electronic, thermoelectric and optoelectronic devices.

A DFT study to explore structural, elastic, mechanical, phonon, electronic and optical properties of halide perovskites AgXF3(X=Be,Ca)$$ {\mathrm{AgXF}}_3\left(\mathrm{X}=\mathrm{Be},\mathrm{Ca}\right) $$ with PBEsol, TB‐mBJ and SCAN functionals

“…It is due to the fact that Ca atom has larger atomic mass and hence larger size. It is consistent with previous studies of similar halide perovskites [25,[46][47][48][49]. The previous study of these perovskites reports that optimized lattice constant of AgBeF 3 (AgCaF 3 ) is 3.660 (4.338Å) obtained with PBEsol [23].…”

First-principles investigation of the ultra-wide band gap halides perovskite XBeF3 (X = Na, K) with pressure effects

“…Analyzing the relationship between the structural stability and physical properties and temperature and pressure is of great significance for a deeper and more comprehensive understanding of the structure and basic physical properties of NaBeF 3 and KBeF 3 crystals. Firstprinciples calculations based on the density functional theory and the pseudopotential method have been widely used in the research and calculation of materials science [12][13][14][15][16][17]. To comprehensively understand the physical properties of NaBeF 3 and KBeF 3 crystals under high pressure, this paper aimed to study the structure, electronic, optical and thermodynamic properties of NaBeF 3 and KBeF 3 crystals at high temperature and pressure using the density functional theory [18] and quasi-harmonic Debye model [19].…”