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relativistic effects in the study of structure and electronic properties of uo2 within dft+u method
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نویسنده
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payami m ,sheykhi s
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منبع
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پژوهش فيزيك ايران - 2023 - دوره : 23 - شماره : 3 - صفحه:141 -146
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چکیده
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Electrons of orbitals near to nuclei of heavy atoms acquire speeds comparable to the speed of light in vacuum. therefore, to study the properties of crystals containing heavy atoms, it is necessary to take into account the relativistic effects. in this work, using the first-principles dft+u method, we have calculated the electronic structure and geometric properties of uranium dioxide uo2 within full-relativistic, scalar-relativistic, and non-relativistic formulations, and compared the results. it is shown that: (i) the non-relativistic scheme gives results very far form experimental values for both lattice constant and bang gap; (ii) in full-relativistic case which the spin-orbit effects are included, the kohn-sham band-gap is increased by 6.2% and the lattice constant decreases by 0.05% compared to scalar-relativistic one. therefore, in the study of geometric properties of uo2, using the scalar-relativistic regime is quite accurate and one does not need to perform much more expensive full-relativistic calculations whenever one does not study the electronic excitation properties.
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کلیدواژه
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uranium dioxide ,anti-ferromagnetism ,density-functional theory ,spin-orbit effect ,mott insulator ,dft+u
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آدرس
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nuclear science and technology research institute, school of physics and accelerators, iran, nuclear science and technology research institute, school of physics and accelerators, iran
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پست الکترونیکی
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ssheykhi@aeoi.org.ir
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relativistic effects in the study of structure and electronic properties of uo2 within dft+u method
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Authors
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Abstract
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electrons of orbitals near to nuclei of heavy atoms acquire speeds comparable to the speed of light in vacuum. therefore, to study the properties of crystals containing heavy atoms, it is necessary to take into account the relativistic effects. in this work, using the first-principles dft+u method, we have calculated the electronic structure and geometric properties of uranium dioxide uo2 within full-relativistic, scalar-relativistic, and non-relativistic formulations, and compared the results. it is shown that: (i) the non-relativistic scheme gives results very far form experimental values for both lattice constant and bang gap; (ii) in full-relativistic case which the spin-orbit effects are included, the kohn-sham band-gap is increased by 6.2% and the lattice constant decreases by 0.05% compared to scalar-relativistic one. therefore, in the study of geometric properties of uo2, using the scalar-relativistic regime is quite accurate and one does not need to perform much more expensive full-relativistic calculations whenever one does not study the electronic excitation properties.
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Keywords
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uranium dioxide ,anti-ferromagnetism ,density-functional theory ,spin-orbit effect ,mott insulator ,dft+u
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