Negative thermal expansion and electronic structure variation of chalcopyrite type LiGaTe<sub>2</sub>

Atuchin, Victor V.; Liang, Fei; Grazhdannikov, S.; Isaenko, L. I.; Krinitsin, P.; Мolokeev, Maxim S.; Prosvirin, Igor P.; Jiang, Xingxing; Lin, Zheshuai

doi:10.1039/c8ra01079j

Cited by 45 publications

(36 citation statements)

References 57 publications

(68 reference statements)

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“…This work is aimed at the systemic study, by computer modeling methods, of the behavior of the vibrational spectra of simple and double metal carbonates under pressure. Previously, such combined approach was successfully applied for the exploration of structural, electronic and spectroscopic characteristics of crystal materials related to different chemical classes [ 23 , 24 , 25 , 26 , 27 , 28 ]. The main regularities of changes in the parameters of the vibrational modes, the quantitative dependences of the wavenumbers on pressure and structural parameters of carbonates, as well as the possibility of determining the structural characteristics from the known wavenumber shifts, will be established.…”

Section: Introductionmentioning

confidence: 99%

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

Zhuravlev

Atuchin

2021

Sensors

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Using the density functional theory with the hybrid functional B3LYP and the basis of localized orbitals of the CRYSTAL17 program code, the dependences of the wavenumbers of normal long-wave ν vibrations on the P(GPa) pressure ν(cm−1) = ν0 + (dv/dP)·P + (d2v/dP2)·P and structural parameters R(Å) (R: a, b, c, RM-O, RC-O): ν(cm−1) = ν0 + (dv/dR) − (R − R0) were calculated. Calculations were made for crystals with the structure of calcite (MgCO3, ZnCO3, CdCO3), dolomite (CaMg(CO3)2, CdMg(CO3)2, CaZn(CO3)2) and aragonite (SrCO3, BaCO3, PbCO3). A comparison with the experimental data showed that the derivatives can be used to determine the P pressures, a, b, c lattice constants and the RM-O metal-oxygen, and the RC-O carbon-oxygen interatomic distances from the known Δν shifts. It was found that, with the increasing pressure, the lattice constants and distances R decrease, and the wavenumbers increase with velocities the more, the higher the ν0 is. The exceptions were individual low-frequency lattice modes and out-of-plane vibrations of the v2-type carbonate ion, for which the dependences are either nonlinear or have negative dv/dP (positive dv/dR) derivatives. The reason for this lies in the properties of chemical bonding and the nature of atomic displacements during these vibrations, which cause a decrease in RM-O and an increase in RC-O.

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Section: Introductionmentioning

confidence: 99%

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

Zhuravlev

Atuchin

2021

Sensors

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“…45 Panels 3B and 3C display the total and partial density of states (DOS), respectively. [47][48][49] In Figure 4, the emission and excitation spectra of a typical LMN:Mn 4+ phosphor (with the Mn 4+ concentration at 0.004 mol%) at room temperature are shown. 45 Figure 3D displays the DRS of the LMN host, which exhibits high reflectance in the UV to visible range except a dramatic drop in the range of 240-300 nm, attributed to the transition from valence to conduction band.…”

Section: Resultsmentioning

confidence: 99%

“…As DFT calculation may underestimate the bandgap more or less, so the experimental value of bandgap corresponds reasonably with the calculated value. [47][48][49] In Figure 4, the emission and excitation spectra of a typical LMN:Mn 4+ phosphor (with the Mn 4+ concentration at 0.004 mol%) at room temperature are shown. The PLE spectrum consists of two excitation bands ranging from 250 to 550 nm, which can be decomposed into four Gaussian sub-bands peaking at 295 nm, 342 nm, 399 nm, and 474 nm, corresponding to the Mn 4+ -O 2− charge transfer band (CTB) and the transitions from the Mn 4+ ground state of 4 A 2g to the excited states ( 4 T 1g , 2 T 2g and 4 T 2g ).…”

Section: Resultsmentioning

confidence: 99%

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

et al. 2019

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Red phosphor is indispensable to achieve warm white light in the white light diode (WLED) application. However, the current red phosphors suffer from high cost and harsh synthesis conditions. In this study, an oxide-based rare-earth-free red-emitting phosphor Li 3 Mg 2 NbO 6 :Mn 4+ (LMN:Mn 4+ ) has been successfully synthesized by a simple solid-state reaction method. The relationship between crystal structure and luminescence was investigated in detail. The site occupancy of the doping Mn 4+ ion in the LMN host has been discussed from the point of bond valence sum. How the coordination environment of doping Mn 4+ affects the energy level of doping Mn 4+ ion has been illustrated via the Tanabe-Sugano energy-level diagram. Moreover, warm white light has been obtained using LMN:Mn 4+ as compensator to the YAG:Ce 3+ . K E Y W O R D Scalculation, luminescence materials, Mn 4+ , phosphor, photoluminescence

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“…The silver chalcogenides are promising superionic semiconductors with low heat conductivity of the lattice as the Ag 2 Se-Ho 2 Se 3 compound [28]. The high potential of LiGaTe 2 for the optical frequency conversion in the mid-IR spectral range has been demonstrated in several studies [29]. These results indicate that LiGaTe 2 , besides its wellknown pronounced linear and nonlinear optical properties in IR spectral range, possesses the specific structural effects.…”

Section: Introductionmentioning

confidence: 95%

First-principles investigations of structural, optoelectronic and thermoelectric properties of Cu-based chalcogenides compounds

et al. 2021

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The structural, electronic, optical and thermoelectric properties of copper-based ternary chalcogenides ACuSe 2 (A = Sc, Y and La) were investigated within the framework of the density functional theory (DFT). The electronic band structures and density of states exhibit that ScCuSe 2 and YCuSe 2 have the indirect band gaps, while LaCuSe 2 displays a direct band gap-type transition. The band structure calculations agree well with other results in the literature. The optical behavior of the studied materials was analyzed in terms of dielectric functions, refractive index, extinction coefficient, absorption coefficient, optical conductivity, reflectivity and energy loss factor. The refractive indices increase to the maximum values of 4.4, 4 and 4.1 at the short infrared and visible wavelengths for ScCuSe 2 , YCuSe 2 and LaCuSe 2 , respectively. Then, they decrease to get a value below 1.0 at the UV wavelengths. Moreover, the material response with temperature was investigated by Seebeck coefficient, figure of merit, specific heat capacity, power factor, thermal conductivity and susceptibility. The high Seebeck effect and large power factor values confirm the efficiency of these materials in thermoelectric energy converter technology. Among the three studied ternary materials, YCuSe 2 has the highest value of dimensionless figure of merit of 0.45 at room temperature. These results would probably provide a new route to the experimentalists for the potential usage and applications of ScCuSe 2 , YCuSe 2 and LaCuSe 2 in thermoelectric and optoelectronic devices.

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Negative thermal expansion and electronic structure variation of chalcopyrite type LiGaTe₂

Abstract: The LiGaTe2 crystals were grown by the Bridgman–Stockbarger technique and the cell parameter dependence on temperature in the range of 303–563 K was evaluated by the X-ray diffraction analysis and first principles calculations.

Cited by 45 publications

References 57 publications

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties

First-principles investigations of structural, optoelectronic and thermoelectric properties of Cu-based chalcogenides compounds

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Negative thermal expansion and electronic structure variation of chalcopyrite type LiGaTe2

Abstract: The LiGaTe2 crystals were grown by the Bridgman–Stockbarger technique and the cell parameter dependence on temperature in the range of 303–563 K was evaluated by the X-ray diffraction analysis and first principles calculations.

Cited by 45 publications

References 57 publications

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

First-Principle Studies of the Vibrational Properties of Carbonates under Pressure

Insight into a novel rare‐earth‐free red‐emitting phosphor Li3Mg2NbO6:Mn4+: Structure and luminescence properties

First-principles investigations of structural, optoelectronic and thermoelectric properties of Cu-based chalcogenides compounds

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Product

Resources

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Negative thermal expansion and electronic structure variation of chalcopyrite type LiGaTe₂

Insight into a novel rare‐earth‐free red‐emitting phosphor Li₃Mg₂NbO₆:Mn⁴⁺: Structure and luminescence properties