相关论文: Possible Orthorhombic Phase of Ta$_2$O$_5$ under H…

We investigate using first-principles calculations the atomic structure of the orthorhombic phase of Ta$_2$O$_5$. Although this structure has been studied for decades, the correct structural model is controversial owing to the complication…

Tantalum pentoxide (Ta2O5) is a polymorphic wide-bandgap semiconductor with outstanding dielectric properties and widespread use in optical and electronic technologies. Its rich structural diversity, arising from multiple polymorphs…

A pressure-induced phase transition, associated with an increase of the coordination number of In and Ta, is detected beyond 13 GPa in InTaO4 by combining synchrotron x-ray diffraction and Raman measurements in a diamond anvil cell with…

Based on particle swarm optimization (PSO) algorithm and density functional theory (DFT) calculations, we identify a stable triclinic crystal structure of Ta2O5 (named as {\gamma}1-Ta2O5) at atmospheric pressure whose unit cell contains one…

In the present work, we report a detailed density functional theory calculation on polymorphic InVO$_4$ phases by means of projector augmented wave method. The computed first-order structural phase transformation from orthorhombic…

We have performed ab initio calculations for new high-pressure phase of Ca-VI between 158-180 GPa. The study includes elastic parameters of mono- and poly-crystalline aggregates, electronic band structure, lattice dynamics and…

The crystal structure of solid oxygen at low temperatures and at pressures up to 7 GPa is studied by theoretical calculations. In the calculations, the adiabatic potential of the crystal is approximated by a superposition of pair-potentials…

Recently is has been shown \cite{Gladden:2024ssb} that strongly coupled ${\cal N}=4$ supersymmetric Yang-Mills plasma with diagonal $U(1)$ $R$-charge chemical potential is unstable at $\frac{\mu}{2\pi T}=\sqrt{2}$. We construct a new…

We provide a systematic study on the electronic structure of a series of Ta$_2$O$_5$ polymorphs using standard density functional theory (DFT) calculations as well as the more accurate many-body perturbation theory within the GW…

The structural behavior of UO2 under high pressure up to 300GPa has been studied by first-principles calculations with LSDA+U approximation. The results show that a pressure-induced structural transition to the cotunnite-type (orthorhombic…

Titanium dioxide has been extensively studied in the rutile or anatase phases, while its high-pressure phases are less well understood, despite that many are thought to have interesting optical, mechanical and electrochemical properties.…

Nuclear quantum effects are essential for correctly describing hydrogen-rich materials at high pressures. Superconducting hydrides and ice are prime examples of such systems, requiring the inclusion of lattice anharmonicity and nuclear…

We suggest a tetragonal $I4_1/amd$ phase ($\eta$-phase) as the ground state of $\mathrm{Ta_2O_5}$ at zero temperature, which is a high symmetry version of the triclinic $\gamma$-phase $\mathrm{Ta_2O_5}$ predicted by Yang and Kawazoe. Our…

By investigating the crystalline structure of ground-state orthorhombic SrRuO$_3$, we present a benchmark study of some of the most popular density functional theory (DFT) approaches from the local density approximation (LDA),…

A structural orthorhombic-to-tetragonal phase transition was recently discovered in the heavy-fermion compound UTe$_2$ at a pressure $p^*\simeq3-8$~GPa [Honda \textit{et al.}, J. Phys. Soc. Jpn. \textbf{92}, 044702 (2023); Huston \textit{et…

While the tetragonal antiferro-electrically distorted (AFD) phase with space group $I4/mcm$ is well known for SrTiO$_3$ to occur below 105 K, there are also some hints in literature of an orthorhombic phase, either at lower temperature at…

Titanium dioxide (TiO2) is a wide band gap semiconducting material which is promising for photocatalysis. Here we present first-principles calculations to study the pressure dependence of structural and electronic properties of two TiO2…

Recent theoretical study has shown that the hexagonal YCo$_5$ is dynamically unstable and distorts into a stable orthorhombic structure. In this study, we show theoretically that the orthorhombic phase is energetically more stable than the…

The structure of solid oxygen has been studied at pressures from 50 to 140~GPa using static structure search methods and molecular dynamics simulations with density functional theory and a hybrid exchange functional. Several crystalline…

By performing constant-pressure variable-cell ab initio molecular dynamics simulations we find a quadrupolar orthorhombic structure, of $Pca2_1$ symmetry, for the broken symmetry phase (phase II) of solid H2 at T=0 and P =110 - 150 GPa. We…