First Principles Investigations on Structural, Elastic, Electronic, and Optical Properties of Li&lt;sub&gt;2&lt;/sub&gt;CdGeS&lt;sub&gt;4&lt;/sub&gt;

Peng, Weimin; Li, Xiaofeng; Du, Junyi

doi:10.2320/matertrans.m2013186

Cited by 3 publications

(3 citation statements)

References 24 publications

(27 reference statements)

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“…The maximum of 38-45% light is likely to be reflected at the peak positions around 2.1 eV, and it is 15-25% around the onset of absorption. The reflectivity spectra of other systems reported elsewhere have similar characteristics (Peng et al, 2013;Ma et al, 2014;Saini et al, 2017;Mohamed et al, 2018). The energy loss function is plotted in Figure 5D.…”

Section: Optical Propertiessupporting

confidence: 71%

The Cs2AgRhCl6 Halide Double Perovskite: A Dynamically Stable Lead-Free Transition-Metal Driven Semiconducting Material for Optoelectronics

Varadwaj

Marques

2020

Front. Chem.

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A-Site doping with alkali ions, and/or metal substitution at the B and B ′-sites, are among the key strategies in the innovative development of A 2 BB ′ X 6 halide double perovskite semiconducting materials for application in energy and device technologies. To this end, we have investigated an intriguing series of five halide-based non-toxic systems, A 2 AgRhCl 6 (A = Li, Na, K, Rb, and Cs), using density functional theory at the SCAN-rVV10 level. The lattice stability and bonding properties emanating from this study of A 2 AgRhCl 6 matched well with those that have already been synthesized, characterized and discussed [viz. Cs 2 AgBiX 6 (X = Cl, Br)]. Exploration of traditional and recently proposed tolerance factors has enabled us to identify A 2 AgRhCl 6 (A = K, Rb and Cs) as stable double perovskites. The band structure and density of states calculations suggested that the electronic transition from the top of the valence band [Cl(3p)+Rh(4d)] to the bottom of the conduction band [(Cl(3p)+Rh(4d)] is inherently direct at the X-point of the first Brillouin zone. The (non-spin polarized) bandgap of these materials was found in the range 0.57-0.65 eV with SCAN-rVV10, which were substantially smaller than those computed with hybrid HSE06 and PBE0, and quasi-particle GW methods. This, together with the appreciable refractive index and high absorption coefficient in the region covering the range 1.0-4.5 eV, enabled us to demonstrate that A 2 AgRhCl 6 (A = K, Rb, and Cs) are likely candidate materials for photoelectric applications. The results of our phonon calculations at the harmonic level suggested that the Cs 2 AgRhCl 6 is the only system that is dynamically stable (no imaginary frequencies found around the high symmetry lines of the reciprocal lattice), although the elastic moduli properties suggested all five systems examined are mechanically stable. Keywords: A 2 AgRhCl 6 halide double perovskites, first-principles studies, optoelectronic properties, geometrical, dynamical and mechanical stabilities, DOS and band structures Varadwaj and Marques Stable Halide Double Perovskites

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Section: Optical Propertiessupporting

confidence: 71%

The Cs2AgRhCl6 Halide Double Perovskite: A Dynamically Stable Lead-Free Transition-Metal Driven Semiconducting Material for Optoelectronics

Varadwaj

Marques

2020

Front. Chem.

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“…The lattice parameters are in good accordance with those given in [23,26]. Li 2 CdGeS 4 and Li 2 CdSnS 4 crystallize in the orthorhombic structure, and Li 2 CdGeS 4 compound is predicted to be stable until 8.6 GPa [44]. The magnitude of the bulk modulus B of Li 2 CdGeS 4 and Li 2 CdSnS 4 quaternary alloys classifies them as easily compressible materials.…”

Section: Computational Details and Crystal Structure Of Materialssupporting

confidence: 80%

“…The total energy of the crystal structures is minimised by varying the volume and relaxing the ionic positions, an equilibrium structure can be reached. The resulting ionic positions, lattice parameters, bulk modulus of LDA as well as data of GGA approximation are presented in table 1 and table 2, and the experimental [26], and theoretical data [23,24,44] are also included for comparison. The lattice parameters are in good accordance with those given in [23,26].…”

Section: Computational Details and Crystal Structure Of Materialsmentioning

confidence: 99%

Investigation of electronic structure and thermodynamic properties of quaternary Li-containing chalcogenide diamond-like semiconductors

Berarma

Charifi

Soyalp

et al. 2016

Semicond. Sci. Technol.

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Using first-principles calculations based on density functional theory, the structural, electronic and thermodynamic properties of Li 2 CdGeS 4 and Li 2 CdSnS 4 compounds are investigated. We confirmed that both Li 2 CdGeS 4 and Li 2 CdSnS 4 are diamond-like semiconductors of the wurtzstannite structure type based on that of diamond in terms of tetrahedra volume. All the tetrahedra are almost regular with major distortion from the ideal occurring in the LiS 4 tetrahedron, with values for S-Li-S ranging from 105.69°to 112.84°in the Li 2 CdGeS 4 compound. Furthermore, the Cd-S bond possesses a stronger covalent bonding strength than the Li/Ge-S bonds. In addition, the inter-distances in Li 2 CdSnS 4 show a larger spread than the distances in the Li 2 CdGeS 4 compound. The electronic structures have been calculated to understand the bonding mechanism in quaternary Li-containing chalcogenide diamond-like semiconductors. Our results show that Li 2 CdGeS 4 and Li 2 CdSnS 4 are semiconductors with a direct band gap of 2.79 and 2.42 eV and exhibit mixed ionic-covalent bonding. It is also noted that replacing Ge by Sn leads to a decrease in the band gap; this behavior is explained in terms of bond lengths and electronegativity differences between atoms. Optical properties, including the dielectric function, reflectivity, and absorption coefficient, each as a function of photon energy are calculated and show an optical anisotropy for Li 2 CdGeS 4 and Li 2 CdSnS 4 . The static dielectric constant e 0 1 ( ) and static refractive index n 0 ( ) decrease when Ge is replaced by Sn. The influence of pressures and temperatures on the thermodynamic properties like the specific heat at constant volume C , v and at constant pressure C , p the Debye temperature Q , D the entropy S and the Grüneisen parameter g have been predicted at enlarged pressure and temperature ranges. The principal aspect from the obtained results is the close similarity of both compounds.

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Revealing the origin of the strong second harmonic generation of Li2CdXS4 and Li2CdXS4 (X = Ge or Sn)

Reshak

2016

Journal of Applied Physics

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Second harmonic generation (SHG) and the first hyperpolarizability (βijk) of two novel quaternary diamond-like semiconductors, Li2CdGeS4 and Li2CdSnS4, are investigated based on the band structure calculations. Calculations show that these materials possess wide and direct energy gaps of about 3.10 eV (Li2CdGeS4) and 3.23 eV (Li2CdSnS4) in close agreement with the measured gaps (3.15 eV and 3.26 eV). The energy gap values confirm that these materials exhibit exceptional laser damage thresholds. The presence of polarizable M-S bonds tunes these compounds to exhibit strong SHG. The calculated linear optical properties exhibit considerable anisotropy, which favors the enhanced phase matching conditions necessary for observation of SHG and optical parametric oscillation. It has been found that Li2CdGeS4 and Li2CdSnS4 exhibit negative uniaxial anisotropy and positive birefringence. The calculated SHG of the dominant component is about 18.64 pm/V for Li2CdGeS4, which is larger than that obtained from Li2CdSnS4 (12.75 pm/V). These results are in concordance with the experimental value of the well known nonlinear crystal KTiOPO4. The calculated first hyperpolarizability (β333) at λ = 1064 nm is about 13.015 × 10−30 esu for Li2CdGeS4 and 9.704 × 10−30 esu for Li2CdSnS4.

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First Principles Investigations on Structural, Elastic, Electronic, and Optical Properties of Li<sub>2</sub>CdGeS<sub>4</sub>

Cited by 3 publications

References 24 publications

The Cs2AgRhCl6 Halide Double Perovskite: A Dynamically Stable Lead-Free Transition-Metal Driven Semiconducting Material for Optoelectronics

The Cs2AgRhCl6 Halide Double Perovskite: A Dynamically Stable Lead-Free Transition-Metal Driven Semiconducting Material for Optoelectronics

Investigation of electronic structure and thermodynamic properties of quaternary Li-containing chalcogenide diamond-like semiconductors

Revealing the origin of the strong second harmonic generation of Li2CdXS4 and Li2CdXS4 (X = Ge or Sn)

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