Related papers: Origin of complex crystal structures of elements a…
Recent high-pressure x-ray diffraction studies of alkali metals revealed unusual complex structures that follow the body-centered and face-centered cubic structures on compression. The structural sequence of potassium under compression to 1…
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…
Most elemental metals under ambient conditions adopt simple structures such as BCC, FCC and HCP in specific groupings across the Periodic Table, and on compression, many of these elements undergo transitions to surprisingly complex…
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,…
I discuss the behaviour of Group 1 and 2 elements under pressure, describing crystallography based on diamond anvil pressure cell experiments and electronic structure calculations. In addition to these precise methods, we discuss more…
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)…
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…
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…
The binary (simple metal) phase diagram Au-Cd contains a number of intermetallic compounds with various distortions, superlattices and vacancies. To understand the reasons of these structural complexities and their phase stability, we…
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…
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…
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 atomic structure of the supercooled liquid has often been discussed as a key source of glass formation in metals. The presence of icosahedrally-coordinated clusters and their tendency to form networks have been identified as one…
Due to increased interest in the unusual magnetic and transport behavior of MnSi and its possible relation to its crystal structure (B20) which has unusual coordination and lacks inversion symmetry, we provide a detailed analysis of the…
The effect of hydrostatic pressure on the electronic structures of iron pnictide superconducting compounds LiFeAs and NaFeAs through density functional theory based first principles studies are presented, using the predicted crystal…
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…
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…
A characteristic property of many soft matter systems is an ultrasoft effective interaction between their structural units. This softness often leads to complex behavior. In particular, ultrasoft systems under pressure demonstrate…
In crystalline systems with a superstructure, the electron dispersion can form a nontrivial covering of the Brillouin zone. It is proved that the number of sheets in this covering and its monodromy are topological invariants under ambient…
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…