Reddy, P V S and V, Kanchana
(2018)
Electronic structure and Fermi surface topology of
binary and ternary compounds.
PhD thesis, Indian Institute of Technology Hyderabad.
Abstract
To explore the material properties, electronic structure calculations are very much useful and
can be obtained from the well known density functional theory(DFT) calculations. In the present
thesis, we have focussed on the Fermi surface calculations and try to link the same with other physical
properties. In addition, we have also explored the pressure effect on properties of the system. For the
present study, we have selected different types of compounds which are Ni-based Heusler compounds,
Nb-based A-15 compounds, Sn-based binary compounds and few magnetic compounds(one Zr-based
Heusler compound and other Mn-based compounds).
Electronic structure, mechanical, vibrational properties of Ni-based Heusler compounds, Ni2XAl
(X=Ti, Zr, Hf, V, Nb, and Ta), Ni2NbGa and Ni2NbSn, are presented both at ambient and under
compression. Among the mentioned compounds, Ni2NbAl, Ni2NbGa and Ni2NbSn are experimentally
reported as superconductors at ambient and our calculated superconducting transition temperature
(Tc) and electron-phonon coupling constant (λep) values are in good agreement with the
experiments. In addition, we have predicted superconducting nature in Ni2VAl with electron-phonon
coupling constant (λep) around 0.68, which leads to superconducting transition temperature (Tc)
around ∼4 K (by using coulomb pseudopotential μ∗ = 0.13), which is a relatively high transition
temperature for Ni based Heusler alloys and are compared with other Ni2NbY (Y = Al, Ga and Sn)
compounds. From the calculated Fermi surfaces, flat Fermi sheets are observed along X-
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