Author: Volodymyr Romaka, Volodymyr Pashkevych, Lyubov Romaka, Yuriy Stadnyk, Vitaliy Romaka, Svitlana Kovtun, Andriy Horyn
Year: 2025
ISBN: 978-966-994-086-5
Publication Language: Ukrainian
Publisher: Publishing House of Lviv Polytechnic National University
Place Published: Lviv
Annotation: The results of research on a new class of thermoelectric materials with high efficiency of converting thermal energy into electrical energy, obtained by doping semi-Heusler semiconductor phases TiNiSn, ZrNiSn, HfNiSn, TiCoSb, VFeSb, ZrCoSb and RNiSb (R is a rare earth metal) with acceptor and/or donor impurities are presented, which allows controlling the position of the Fermi level, changing the values of electrical resistance, thermopower coefficients and thermal conductivity. The study of structural, thermodynamic, electrokinetic, energy and magnetic properties of thermoelectric materials made it possible to establish the features of transformations of their crystal and electronic structures, mechanisms of electrical conductivity. Physical principles for optimizing the properties of semi-Heusler phases to obtain maximum values of thermoelectric figure of merit are formulated and implemented. In particular, an algorithm for controlling the properties of thermoelectric materials has been developed by modeling them using the KKR methods (AkaiKKR package for the MJW potential) and FLAPW within the framework of the density functional theory DFT (Vienna Ab initio Simulation Package VASP v. 5.4.4) and cyclic correction of the initial conditions of calculations with the parameters of experimental measurements. For researchers, postgraduates and students of the specialties of metrology and information and measurement technology, materials science, micro- and nanosystem technology, applied physics and nanomaterials.
Keywords: semiconductor, Fermi level, thermoelectromotive force, electrical resistance, thermoEMF coefficient, electrons, vacancy, kinetic properties, thermodynamic properties, crystal structure, electronic structure, thermal conductivity.