THEORETICAL EVIDENCE FOR UNUSUAL BONDING GEOMETRY AND PHASE TRANSITIONS OF Na ON Al(001)

1994 ◽  
Vol 01 (02n03) ◽  
pp. 213-219 ◽  
Author(s):  
C. STAMPFL ◽  
J. NEUGEBAUER ◽  
M. SCHEFFLER
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
Phase Transitions ◽  
Density Functional ◽  
Alkali Metals ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Island Formation ◽  
Low Concentration ◽  
Theoretical Evidence

We performed density-functional theory calculations for Na on Al(001) for various coverages from a very low concentration up to a monolayer. From the results we predict that for low coverages the Na atoms occupy on-surface hollow sites which is the stable geometry, but for higher coverages this is only metastable; the stable geometry is reached through a phase transition to a condensed c(2×2) structure where the Na atoms are in surface substitutional sites (contrary to previously suggested models). The mechanism which actuates the island formation with a substitutional geometry is described and the differences to the substitutional adsorption of alkali metals on Al(111) are discussed.

scholarly journals Crossover from metal to insulator in dense lithium-rich compound CLi4

2016 ◽  
Vol 113 (9) ◽  
pp. 2366-2369 ◽  
Author(s):  
Xilian Jin ◽  
Xiao-Jia Chen ◽  
Tian Cui ◽  
Ho-kwang Mao ◽  
Huadi Zhang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
Fermi Surface ◽  
Density Functional ◽  
Alkali Metals ◽  
Alkaline Earth ◽  
Density Functional Theory Calculations ◽  
Alkaline Earth Metals ◽  
Functional Theory ◽  
Surface Filling

At room environment, all materials can be classified as insulators or metals or in-between semiconductors, by judging whether they are capable of conducting the flow of electrons. One can expect an insulator to convert into a metal and to remain in this state upon further compression, i.e., pressure-induced metallization. Some exceptions were reported recently in elementary metals such as all of the alkali metals and heavy alkaline earth metals (Ca, Sr, and Ba). Here we show that a compound of CLi4 becomes progressively less conductive and eventually insulating upon compression based on ab initio density-functional theory calculations. An unusual path with pressure is found for the phase transition from metal to semimetal, to semiconductor, and eventually to insulator. The Fermi surface filling parameter is used to describe such an antimetallization process.

scholarly journals Predicted polymorph manipulation in an exotic double perovskite oxide

2019 ◽  
Vol 7 (39) ◽  
pp. 12306-12311 ◽  
Author(s):  
He-Ping Su ◽  
Shu-Fang Li ◽  
Yifeng Han ◽  
Mei-Xia Wu ◽  
Churen Gui ◽  
...  
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Double Perovskite ◽  
Density Functional Theory Calculations ◽  
Perovskite Oxide ◽  
Functional Theory ◽  
First Time ◽  
Perovskite Type

First-principles density functional theory calculations, for the first time, was used to predict the Mg3TeO6-to-perovskite type phase transition in Mn3TeO6 at around 5 GPa.

Janus monolayer of WSeTe, a new structural phase transition material driven by electrostatic gating

Nanoscale ◽  
2018 ◽  
Vol 10 (46) ◽  
pp. 21629-21633 ◽  
Author(s):  
Yajing Sun ◽  
Zhigang Shuai ◽  
Dong Wang
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
Structural Phase Transition ◽  
Density Functional ◽  
Structural Phase ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electrostatic Gating ◽  
Phase Transition Kinetics

By density functional theory calculations, we show that the Janus monolayer of WSeTe has faster semiconductor–semimetal phase transition kinetics than MoTe2.

scholarly journals Density-functional study of pressure-induced phase transitions and electronic properties of Zn2V2O7

RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 10401-10415
Author(s):  
Daniel Díaz-Anichtchenko ◽  
Lourdes Gracia ◽  
Daniel Errandonea
Keyword(s):  
Density Functional Theory ◽  
Phase Transitions ◽  
Electronic Properties ◽  
Density Functional ◽  
Structural Changes ◽  
Density Functional Theory Calculations ◽  
Functional Study ◽  
Functional Theory ◽  
Density Functional Study

Phase transitions induced by pressure in zinc pyrovanadate have been understood using density-functional theory calculations. Consequences of structural changes on electronic properties are discussed.

Is a Non-Transition Element Nitride Ferromagnet Ever Achievable? Indication of the N-N Pairing Instability

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition Element ◽  
Density Functional Theory Calculations ◽  
Functional Theory

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.

scholarly journals Tensor-structured algorithm for reduced-order scaling large-scale Kohn–Sham density functional theory calculations

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Chih-Chuen Lin ◽  
Phani Motamarri ◽  
Vikram Gavini
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Large Scale ◽  
Density Functional Theory Calculations ◽  
System Size ◽  
Real Space ◽  
Functional Theory ◽  
Reduced Order ◽  
Separable Approximation ◽  
Tensor Basis

AbstractWe present a tensor-structured algorithm for efficient large-scale density functional theory (DFT) calculations by constructing a Tucker tensor basis that is adapted to the Kohn–Sham Hamiltonian and localized in real-space. The proposed approach uses an additive separable approximation to the Kohn–Sham Hamiltonian and an L1 localization technique to generate the 1-D localized functions that constitute the Tucker tensor basis. Numerical results show that the resulting Tucker tensor basis exhibits exponential convergence in the ground-state energy with increasing Tucker rank. Further, the proposed tensor-structured algorithm demonstrated sub-quadratic scaling with system-size for both systems with and without a gap, and involving many thousands of atoms. This reduced-order scaling has also resulted in the proposed approach outperforming plane-wave DFT implementation for systems beyond 2000 electrons.

scholarly journals Polymorphs of Rb3ScF6: X-ray and Neutron Diffraction, Solid-State NMR, and Density Functional Theory Calculations Study

2021 ◽  
Vol 60 (8) ◽  
pp. 6016-6026
Author(s):  
Aydar Rakhmatullin ◽  
Maxim S. Molokeev ◽  
Graham King ◽  
Ilya B. Polovov ◽  
Konstantin V. Maksimtsev ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Neutron Diffraction ◽  
Solid State Nmr ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document