Theoretical Study of Structural, Elastic Properties and Phase Transitions of Cu2ZnSnS4

2014 ◽  
Vol 1058 ◽  
pp. 113-117 ◽  
Author(s):  
Yi Feng Zhao ◽  
Zu Ming Liu ◽  
De Cong Li
Keyword(s):  
Phase Transitions ◽  
Elastic Properties ◽  
Density Functional ◽  
Theoretical Work ◽  
Structure Stability ◽  
Ground State Structure ◽  
Preparation Technology ◽  
Functional Theory ◽  
Unstable Phase ◽  
Total Energies

The total energy, the electronic properties, phase transitions, and elastic properties of Cu2ZnSnS4(CZTS) in the three structures are investigated by first-principles calculations based on density functional theory. Results show that the total energies of stannite (ST) and primitive-mixed CuAu (PMCA) structures are higher than that of kesterite-type (KS), and the KS is the ground state structure. Relationships between enthalpy and pressure of the KS, ST and PMCA structure of CZTS are also investigated at 0 K, since the pressure can have profound impacts on the electronic structure, possible phase transitions and structure stability. And results also show that KS structure is always the most stable; ST is the second; and the PMCA structure is the most unstable; phase transitions of three structures could not occur in high pressure. The high ratios of shear modulus to bulk modulus (G/B) indicate that CZTS compounds in three types have ductile behaviors. The Poisson ratios for the three structures are from 0.27 to 0.31, which again proves that all structures of CZTS have better plasticity. The results can increase more hints about further research directions, and these effects can play an important role in future experimental preparation technology and theoretical work of CZTS materials.

A DFT study of pressure-induced phase transitions, structural and electronic properties of Cu2ZnSnS4

2016 ◽  
Vol 30 (16) ◽  
pp. 1650176 ◽  
Author(s):  
Yifen Zhao ◽  
Decong Li ◽  
Zuming Liu
Keyword(s):  
Phase Transitions ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Theoretical Work ◽  
Functional Theory ◽  
Phase Transition Pressure ◽  
Structural And Electronic Properties ◽  
Direct Band

The structural properties, phase transitions, and electronic structures of Cu2ZnSnS4 (CZTS) in the three structures have been researched using the first-principles density functional theory (DFT). The results indicate that the energies of stannite (ST) and pre-mixed Cu–Au (PMCA) CZTS are higher than those of kesterite (KS) CZTS, indicating that the KS CZTS is more stable. We found the phase transition pressure between the KS and ST structures of CZTS is about 32 GPa. Moreover, for KS- and PMCA-CZTS, there exists in the mischcrystal phase between 52 GPa and 65 GPa. The band structures show that the KS- and ST-CZTS are direct band gap semiconductors. The band gaps of three-type CZTS increase with increasing pressure, and the maximum band gap of KS and ST structures for CZTS occurs at 50 GPa. However, PMCA CZTS possesses metal property. Furthermore, the PMCA CZTS translates from metal to the indirect semiconductor with increasing pressure. The results play an important role in future experimental and theoretical work for CZTS materials.

DFT study on thermo-elastic properties of Ru2FeZ (Z = Si, Ge, Sn) Heusler alloys

2018 ◽  
Vol 32 (05) ◽  
pp. 1850045 ◽  
Author(s):  
Aneeza Iftikhar ◽  
Afaq Ahmad ◽  
Iftikhar Ahmad ◽  
Muhammad Rizwan
Keyword(s):  
Thermal Stability ◽  
Elastic Properties ◽  
Density Functional ◽  
Heusler Alloys ◽  
Longitudinal Mode ◽  
Transverse Mode ◽  
Functional Theory ◽  
Formation Energies ◽  
Thermal Stability Of ◽  
Temperature Melting

We studied the thermo-elastic properties of Ru2FeZ (Z[Formula: see text]=[Formula: see text]Si, Ge, Sn) Heusler alloys within the framework of density functional theory. Thermo-elastic properties corresponding to elastic modulus, anisotropy, phase stability, elastic wave velocities, thermal stability, Debye temperature, melting temperature, thermal conductivity and formation energy are calculated. The elastic constants C[Formula: see text] predict the structural and dynamical stabilities while the formation energies show thermal stability of the alloys at 0 K. Pugh’s and Poisson’s ratios display the ductile nature of alloys. All alloys are anisotropic and we also observed that Ru2FeSn is the hardest material than Ru2FeSi and Ru2FeGe. Moreover, longitudinal mode of vibrations are also observed and are maximum along [100], [110] and [111] directions than the transverse mode of vibrations.

Structure, stability and intramolecular interaction of M(N5)2(M = Mg, Ca, Sr and Ba) : a theoretical study

RSC Advances ◽  
2015 ◽  
Vol 5 (28) ◽  
pp. 21823-21830 ◽  
Author(s):  
Xueli Zhang ◽  
Junqing Yang ◽  
Ming Lu ◽  
Xuedong Gong
Keyword(s):  
Energetic Materials ◽  
Density Functional ◽  
Alkaline Earth ◽  
Theoretical Study ◽  
Intramolecular Interaction ◽  
Earth Metal ◽  
Structure Stability ◽  
Alkaline Earth Metal ◽  
Functional Theory ◽  
The Density Functional Theory

The potential energetic materials, alkaline earth metal complexes of the pentazole anion (M(N5)2, M = Mg2+, Ca2+, Sr2+and Ba2+), were studied using the density functional theory.

First-Principles Analysis on Interaction between Dopant (Ga, Sb) and Contamination Metal Atoms in Ge Crystals

2013 ◽  
Vol 205-206 ◽  
pp. 417-421
Author(s):  
Tatsunori Yamato ◽  
Koji Sueoka ◽  
Takahiro Maeta
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Functional Theory ◽  
Substitutional Site ◽  
Metal Impurities ◽  
Metal Atoms ◽  
Total Energies ◽  
Group 3

The lowest energetic configurations of metal impurities in 4throw (Sc - Zn), 5throw (Y - Cd) and 6throw (Hf - Hg) elements in Ge crystals were determined with density functional theory calculations. It was found that the substitutional site is the lowest energetic configuration for most of the calculated metals in Ge. The most stable configurations of dopant (Ga, Sb) - metal complexes in Ge crystals were also investigated. Following results were obtained. (1) For Ga dopant, 1st neighbor T-site is the most stable for metals in group 3 to 7 elements while substitutional site next to Ga atom is the most stable for metals in group 8 to 12 elements. (2) For Sb dopant, substitutional site next to Sb atom is the most stable for all calculated metals. Binding energies of the interstitial metalMiwith the substitutional dopantDswere obtained by the calculated total energies. The calculated results for Ge were compared with those for Si.

scholarly journals Lattice Location of Deuterium in Plasma and Gas Charged Mg Doped GaN

1999 ◽  
Vol 595 ◽  
Author(s):  
W. R. Wampler ◽  
J. C. Barbour ◽  
C. H. Seager ◽  
S. M. Myers ◽  
A. F. Wright ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Lattice Relaxation ◽  
Functional Approach ◽  
Functional Theory ◽  
Ion Channeling ◽  
Total Energies ◽  
Lattice Locations ◽  
Mg Doped

AbstractWe have used ion channeling to examine the lattice configuration of deuterium in Mg doped GaN grown by MOCVD. The deuterium is introduced by exposure to gas phase or ECR plasmas. A density functional approach including lattice relaxation, was used to calculate total energies for various locations and charge states of hydrogen in the wurtzite Mg doped GaN lattice. Results of channeling measurements are compared with channeling simulations for hydrogen at lattice locations predicted by density functional theory.

scholarly journals Compression Behavior and Vibrational Properties of New Energetic Material LLM-105 Analyzed Using the Dispersion-Corrected Density Functional Theory

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6831
Author(s):  
Tianming Li ◽  
Junyu Fan ◽  
Zhuoran Wang ◽  
Hanhan Qi ◽  
Yan Su ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Uniaxial Compression ◽  
Density Functional ◽  
Structural Parameters ◽  
Energetic Material ◽  
Structure Stability ◽  
Vibrational Properties ◽  
Detailed Knowledge ◽  
Functional Theory

The 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is a newly energetic material with an excellent performance and low sensitivity and has attracted considerable attention. On the basis of the dispersion-corrected density functional theory (DFT-D), the high-pressure responses of vibrational properties, in conjunction with structural properties, are used to understand its intermolecular interactions and anisotropic properties under hydrostatic and uniaxial compressions. At ambient and pressure conditions, the DFT-D scheme could reasonably describe the structural parameters of LLM-105. The hydrogen bond network, resembling a parallelogram shape, links two adjacent molecules and contributes to the structure stability under hydrostatic compression. The anisotropy of LLM-105 is pronounced, especially for Raman spectra under uniaxial compression. Specifically, the red-shifts of modes are obtained for [100] and [010] compressions, which are caused by the pressure-induced enhance of the strength of the hydrogen bonds. Importantly, coupling modes and discontinuous Raman shifts are observed along [010] and [001] compressions, which are related to the intramolecular vibrational redistribution and possible structural transformations under uniaxial compressions. Overall, the detailed knowledge of the high-pressure responses of LLM-105 is established from the atomistic level. Uniaxial compression responses provide useful insights for realistic shock conditions.

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