This article thoroughly addresses the structural, mechanical, vibrational, electronic band structure and the optical properties of the unexplored thallous perchlorate and perbromate from ab-initio calculations. The zone centered vibrational phonon frequencies shows, there is a blue shift in the mid and high frequency range from Cl → Br due to change in mass and force constant with respect to oxygen atom. From the band structure it is clear that the top of the valence band is due to thallium s states, whereas the bottom of the conduction band is due to halogen s and oxygen p states, showing similar magnitude of dispersion and exhibits a charge transfer character. These characteristics and the band gap obtained are consistent with that of a favourable scintillators. Our findings deliver directions for the design of efficient TlXO4 based scintillators with high performance which are desirable for distinct applications such as medical imaging, high energy physics experiments, nuclear security.

We investigate and quantify bipartite and tripartite entanglement measures in two- and three-flavor neutrino oscillations. The bipartite entanglement is analogous to the entanglement swapping resulting from a beam splitter in quantum optics. We calculate various entanglement measures, such as the concurrence, negativity, and three-tangle for the three-neutrino system. The significant result is that a monogamy inequality in terms of negativity leads to a residual entanglement, implying genuine tripartite entanglement in the three-neutrino system. We establish an analogy of the three-neutrino state with a generalized W-state class in quantum optics.

We examine various aspects and the origin of ferroelastic structural transition in Ba2ZnTeO6 using Raman spectroscopy and first-principles calculations investigating the phonon behavior.

Half-metallic ferromagnetic full Heusler alloy NiFeMnSn is a promising material in spintronic device fabrication as it carries high spin polarization and high Curie temperature (Tc = 405 K). Understanding electronic excitations in a spin-polarized band structure is essential for the further use of this material in spin-based devices and to optimize the spin-dependent electronic structure in related compounds. In this Letter, we report electronic Raman scattering of NiFeMnSn with spectral signatures at a higher wavenumber than expected from the calculated phonon modes of the system. Temperature-dependent Raman spectroscopy demonstrates a non-monotonic behavior of the Raman shift with temperature across Tc. The orbital resolved electronic density of states and electronic band structure for both spin channels of the system, as obtained from the first principles density functional theory calculations, suggest that the observed Raman signatures originate from the Fe d orbital and its splitting due to the crystal field near the Fermi level. Furthermore, a strong magnetic field dependence of the spectral profile is observed. The study not only exhibits electronic Raman scattering in a Heusler alloy compound, which was unexplored to date, but also establishes Raman scattering as a promising probe to study the orbital-resolved partial density of states in the band structure near the Fermi level of a Heusler alloy.

Recently, ABO 4 -type ternary metal oxides have received considerable attention because of their wide range of properties and applications in fundamental physics, chemistry, and materials science. [1][2][3] Exploring the ABO 4 materials is both challenging and interesting because of the variety of structures that have been observed in these oxides. The most common structural types are scheelite, zircon, wolframite, monazite, baryte, fergusonite, and pseudoscheelite. These all contain BO 4 tetrahedra and temperature-and/or pressure-induced structural phase transitions between these are well documented; for example, the transformation from monazite to scheelite to zircon with increasing temperature and from zircon to monazite to scheelite with increasing pressure. [4] This structural versatility leads to a variety of physical features that enables a diverse and broad range of applications, distinguishing ABO 4 -type compounds from other materials. Applications include phosphors (ZrGeO 4 and HfGeO 4 ), battery materials (CaMoO 4 and SrWO 4 ), laser host materials (BaWO 4 and GdTaO 4 ), and scintillators (CdWO 4 and PbWO 4 ). [5] High pressure studies show that the scintillating properties of orthovanadates are better when compared to periodates. [6][7][8] Our recent study suggests that thallous perchlorate and perbromate can be used as inorganic scintillators, since there exists a charge-transfer character in the bands. [9] It is generally found that the structure of the ABO 4 oxides favored under ambient conditions is dependent on the smaller, more highly charged, B-type cation. Phosphates, silicates, vanadates, chromates, and arsenates are known to crystallize in the zircon-type structure, although several phosphates and arsenates crystallize in the quartz structure, whereas the scheelite structure is observed for numerous molybdates, tungstates, iodates, and germanates. [10] The ABO 4 -type compounds where B is technetium (Tc), that is, the pertechnetate group (TcO À1 4 ) have been less well explored. Tc is the first man-made transition metal, and it is the lightest radioactive synthetic element. Tc is the mostly widely utilized radiopharmaceutical and it has been found useful as a corrosion inhibitor in the steel industry, as a superconductor at a very low temperature [11] and also as an environmental water tracer. [12,13] Transition-metal oxides are fascinating to study because of their high melting temperatures and densities, and the capacity of transition metals to form compounds with other elements as well as the potential for transmutation from one compound to another. [14,15] Of the 21 known isotopes of Tc, 99 Tc is the most abundant, and it is a significant by-product of the fission of