High-Temperature and High-Pressure Study of Electronic and Thermal Properties of PbTaO3 and SnAlO3 Metal Perovskites by Density Functional Theory Calculations

2017 ◽  
Vol 47 (1) ◽  
pp. 436-442 ◽  
Author(s):  
Shakeel Ahmad Khandy ◽  
Ishtihadah Islam ◽  
Zahid Saleem Ganai ◽  
Dinesh C. Gupta ◽  
Khursheed Ahmad Parrey
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Thermal Properties ◽  
High Temperature ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
High Pressure Study

scholarly journals Higher superconducting transition temperature by breaking the universal pressure relation

2019 ◽  
Vol 116 (6) ◽  
pp. 2004-2008 ◽  
Author(s):  
Liangzi Deng ◽  
Yongping Zheng ◽  
Zheng Wu ◽  
Shuyuan Huyan ◽  
Hung-Cheng Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Temperature ◽  
Transition Temperature ◽  
Density Functional ◽  
High Temperature Superconductors ◽  
Density Functional Theory Calculations ◽  
Universal Relation ◽  
Superconducting Transition ◽  
Functional Theory ◽  
A Charge

By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconducting transition temperatures (Tcs) of the monolayer Bi2Sr2CuO6+δ(Bi2201) and bilayer Bi2Sr2CaCu2O8+δ(Bi2212) to beyond the maximum Tcs (Tc-maxs) predicted by the universal relation between Tcand doping (p) or pressure (P) at higher pressures. The Tcof underdoped Bi2201 initially increases from 9.6 K at ambient to a peak at 23 K at 26 GPa and then drops as expected from the universal Tc-P relation. However, at pressures above 40 GPa, Tcrises rapidly without any sign of saturation up to 30 K at 51 GPa. Similarly, the Tcfor the slightly overdoped Bi2212 increases after passing a broad valley between 20 and 36 GPa and reaches 90 K without any sign of saturation at 56 GPa. We have, therefore, attributed this Tcresurgence to a possible pressure-induced electronic transition in the cuprate compounds due to a charge transfer between the Cu 3dx2−y2and the O 2pbands projected from a hybrid bonding state, leading to an increase of the density of states at the Fermi level, in agreement with our density functional theory calculations. Similar Tc-P behavior has also been reported in the trilayer Br2Sr2Ca2Cu3O10+δ(Bi2223). These observations suggest that higher Tcs than those previously reported for the layered cuprate high-temperature superconductors can be achieved by breaking away from the universal Tc-P relation through the application of higher pressures.

A high-pressure study of HfC and nano-crystalline TiC by X-ray diffraction and density functional theory calculations

2020 ◽  
Vol 34 (34) ◽  
pp. 2050393
Author(s):  
Lun Xiong ◽  
Bin Li ◽  
Bi Liang ◽  
Jinxia Zhu ◽  
Hong Yi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Bulk Modulus ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Nano Crystalline

The equation of state (EOS) of HfC and nanosized TiC at high pressure has been studied by means of synchrotron radiation X-ray diffraction (XRD) in a diamond anvil cell (DAC) at ambient temperature, and density functional theory (DFT) calculations. XRD analysis showed that the cubic structure of HfC and nanosized TiC maintained to the maximum pressures. The XRD data yield a bulk modulus [Formula: see text] GPa with [Formula: see text] of HfC. In addition, the bulk modulus of nanosized TiC derived from XRD data is [Formula: see text] GPa with [Formula: see text].

scholarly journals Novel superconducting structures of BH2 under high pressure

2019 ◽  
Vol 21 (10) ◽  
pp. 5466-5473 ◽  
Author(s):  
Wen-Hua Yang ◽  
Wen-Cai Lu ◽  
Shan-Dong Li ◽  
Xu-Yan Xue ◽  
Qing-Jun Zang ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Density Functional Theory ◽  
High Pressure ◽  
Crystal Structures ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Genetic Algorithm Method

The high-pressure crystal structures and superconductivity of BH2 were studied using the genetic algorithm method combined with first-principles density functional theory calculations.

Pressure-induced chemical decomposition of copper orthovanadate (α-Cu3V2O8)

2021 ◽  
Author(s):  
Daniel Diaz-Anichtchenko ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Simone Anzellini ◽  
Srungarpu N. Achary ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Theoretical Density ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Chemical Decomposition ◽  
X Ray ◽  
Pressure Stability

The high pressure stability of α-Cu3V2O8 has been investigated via complementary high pressure synchrotron X-ray diffraction experiments and theoretical density functional theory calculations. The results of both experiment and theory...

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