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In present study, we report an inter-comparison of various physical and electronic properties of MgB2 and AlB2. Interestingly, the sign of S(T) is +ve for MgB2 the same is -ve for AlB2. This is consistent our band structure plots. We fitted the experimental specific heat of MgB2 to Debye Einstein model and estimated the value of Debye temperature (theta) and Sommerfeld constant (gamma) for electronic specific heat. Further, from gamma the electronic density of states (DOS) at Fermi level N(EF) is calculated. From the ratio of experimental N (EF) and the one being calculated from DFT, we obtained value of Lembda to be 1.84, thus placing MgB2 in the strong coupling BCS category. The electronic specific heat of MgB2 is also fitted below Tc using pi-model and found that it is a two gap superconductor. The calculated values of two gaps are in good agreement with earlier reports. Our results clearly demonstrate that the superconductivity of MgB2 is due to very large phonon contribution from its stretched lattice. The same two effects are obviously missing in AlB2 and hence it is not superconducting. DFT calculations demonstrated that for MgB2 the majority of states come from Sigma and Pi 2p states of boron on the other hand Sigma band at Fermi level for AlB2 is absent. This leads to a weak electron phonon coupling and also to hole deficiency as Pi bands are known to be of electron type and hence obviously the AlB2 is not superconducting. The DFT calculations are consistent with the measured physical properties of the studied borides, i.e., MgB2 and AlB2
The effect of high pressures to 40 GPa on the crystal structure and lattice dynamics of AlB2 was studied by synchrotron x-ray powder diffraction, Raman spectroscopy, and first-principles calculations. There are no indications for a pressure-induced s
Two types of MgB2 films were prepared by pulsed laser deposition (PLD) with in situ and ex situ annealing processes respectively. Significant differences in properties between the two types of films were found. The ex situ MgB2 film has a Tc of 38.1K
The strain effect on electronic structure and thermoelectric properties of Higher Manganese Silicides (HMSs) Mn4Si7 was studied using Density Functional Theory (DFT) and through solving Boltzman Transport Equation (BTE). We found that the tensile str
The concept of quantum stress (QS) is introduced and formulated within density functional theory (DFT), to elucidate extrinsic electronic effects on the stress state of solids and thin films in the absence of lattice strain. A formal expression of QS
We extend the two leading methods for the emph{ab initio} computational descrip tion of phonon-mediated superconductors, namely Eliashberg theory and density fu nctional theory for superconductors (SCDFT), to include plasmonic effects. Furth ermore,