Related papers: Potassium under pressure: electronic origin of com…
Lithium - the lightest alkali metal - exhibits unexpected structures and electronic behaviour at high pressures. As the heavier alkalis, Li is bcc at ambient pressure and transforms first to fcc (at 7.5 GPa). The post-fcc high-pressure form…
Elements of group I in the Periodic table have valence electrons of s-type and are usually considered as simple metals. Crystal structures of these elements at ambient pressure are close-packed and high-symmetry of bcc and fcc types,…
Simple cubic structure with one atom in the unit cell found in compressed calcium is contrintuitive with regards to traditional view on tendency of transition to densely packed structures on the increase of pressure. To understand this…
Alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We…
Group I elements - alkali metals Li, Na, K, Rb and Cs - are examples of simple metals with one s electron in the valence band. Under pressure these elements display unusually complex structural behaviour transforming from close-packed to…
We present a unifying theory for the observed complex structures of the sp-bonded elements under pressure based on nearly free electron picture (NFE). In the intermediate pressure regime the dominant contribution to crystal structure arises…
Formation of the complex structure with 16 atoms in the orthorhombic cell, space group Cmca (Pearson symbol oC16) was experimentally found under high pressure in the alkali elements (K, Rb, Cs) and polyvalent elements of groups IV (Si, Ge)…
Crystal structures of simple metals and binary alloy phases based on the close-packed hexagonal structure are analyzed within the model of Fermi sphere-Brillouin zone interactions to understand distortions and superlattices. Examination of…
The simple alkali metal Na, that crystallizes in a body-centred cubic structure at ambient pressure, exhibits a wealth of complex phases at extreme conditions as found by experimental studies. The analysis of the mechanism of stabilization…
First-principles density-functional-theory calculations show that compression of alkali metals stabilizes open structures with localized interstitial electrons which may exhibit a Stoner-type instability towards ferromagnetism. We find…
An incommensurate modulated structure was found recently in a light group V element phosphorous in the phase P-IV stable in the pressure range 107-137 GPa. We consider configurations of the Brillouin zone and Fermi sphere within a…
We have calculated the electronic structure of Eu for the bcc, hcp, and fcc crystal structures for volumes near equilibrium up to a calculated 90 GPa pressure using the augmented-plane wave method in the local-density approximation. The…
The paper presents ab initio results on the structural phase stability of beryllium and magnesium crystals under high and ultrahigh pressures (multi-terapascal regime). Magnesium is shown to undergo a number of structural transformations…
The electronic structures of element cerium under high pressure remain unclear all the time. We tried to calculate the electronic structures of $\alpha'$, $\alpha"$, and $\epsilon$-Ce which only exist in the presence of pressure, by using…
Recent experimental results on two hcp phases of barium under high pressure show interesting variation of the lattice parameters. They are here interpreted in terms of electronic structure calculation by using the LMTO method and…
A heavy-fermion paramagnet UTe$_2$ has been a strong candidate for a spin-triplet superconductor. Experiments on UTe$_2$ under pressure have been vigorously conducted, and rich phase diagrams have been suggested. Multiple superconducting…
Binary alloy phases of the noble metals with main group elements are analyzed in relation to body centered cubic structure with orthorhombic and hexagonal distortions. Stability of these distorted phases is considered on the base of the…
The multiband nature of iron-pnictide superconductors is one of the keys to the understanding of their intriguing behavior. The electronic and magnetic properties heavily rely on the multiband interactions between different electron and…
Metal crystals with tetrahedral packing are known as Frank-Kasper phases with large unit cells with the number of atoms from hundreds to thousands. The main factors of the formation and stability of these phases are the atomic size ratio…
The results of electronic structure calculations for a variety of palladium hydrides are presented. The calculations are based on density functional theory and used different local and semilocal approximations. The thermodynamic stability…