Adsorption energetics: First principles calculations of adatom interactions and induced local lattice relaxation

To clarify the origin of a characteristic fine grain structure formed under the high burn-up of the nuclear fuel, the comprehensive first-principles calculations for UO2 containing various types of point defect have been performed by the PAW-GGA+U with lattice relaxation for supercells containing 1, 2 and 8 unit cells of UO2. The electronic structure, the atomic displacement and the defect formation energies of defective systems are obtained, and the effects of supercell size on these properties are discussed. Based on this relatively high precise self-consistent formation energies dataset, thermodynamic properties of various types of point defects in UO2 are further investigated in the framework of the point defects model.

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Identification of Mg Vacancy in MgO by Positron Lifetime Measurements and First-Principles Calculations

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.242-244.1 ◽

2005 ◽

Vol 242-244 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Masataka Mizuno ◽

Hideki Araki ◽

Yasuharu Shirai ◽

Fumiyasu Oba ◽

Isao Tanaka

Keyword(s):

First Principles ◽

Positron Lifetime ◽

Dopant Concentration ◽

Lattice Relaxation ◽

Single Crystal Sample ◽

First Principles Calculations ◽

Lifetime Measurements ◽

Crystal Sample ◽

Trapping Model ◽

Positron Lifetimes

The formation of Mg vacancy induced by ultra-dilute trivalent impurities in MgO is investigated by a combination of positron lifetime measurements and first-principles calculations. The undoped MgO yields the shortest positron lifetime of 140 ps that is shorter than that of a single crystal sample. The positron lifetime of the doped samples increases with the increase of the Al dopant concentration and is saturated at around 180 ps. This result clearly indicates that the formation of Mg vacancy is induced by Al dopant. The concentration of the other trivalent impurities can be evaluated using the result of component analysis of positron lifetimes. The experimental bulk lifetime of 130 ps, which is obtained by employing trapping model, is well reproduced by the theoretical calculation using the semiconductor model. The calculated defect lifetime is about 20 ps longer than the experimental value. This may be due to the lattice relaxation around Mg vacancy associated with the trapping of positrons.

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First principles calculations of lattice relaxation at low index surfaces of Cu

Surface Science ◽

10.1016/0039-6028(93)90556-y ◽

1993 ◽

Vol 286 (1-2) ◽

pp. 66-72 ◽

Cited By ~ 68

Author(s):

Th. Rodach ◽

K.-P. Bohnen ◽

K.M. Ho

Keyword(s):

First Principles ◽

Lattice Relaxation ◽

First Principles Calculations

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First Principles Investigations of Structural and Magnetic Properties of Fe-Ni-Mn-Al Heusler Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.233-234.187 ◽

2015 ◽

Vol 233-234 ◽

pp. 187-191 ◽

Cited By ~ 3

Author(s):

Vasiliy D. Buchelnikov ◽

Marina A. Klyuchnikova ◽

Mikhail A. Zagrebin ◽

Vladimir V. Sokolovskiy

Keyword(s):

Magnetic Properties ◽

Crystal Lattice ◽

Structural Properties ◽

First Principles ◽

Magnetic Order ◽

Heusler Alloys ◽

Lattice Relaxation ◽

Al Alloys ◽

First Principles Calculations ◽

Structural And Magnetic Properties

In this work the magnetic and structural properties of quaternary Fe-Ni-Mn-Al Heusler alloys are studied. We use first principles calculations to investigate crystal lattice relaxation of alloys and their coupling to the magnetic order, with a particular focus on the tetragonal distortions characterized by the c/a ratio. It follows from our calculations that Fe-Ni-Mn-Al alloys have very interesting magnetic properties and can be good candidates as multifunctional magnetic materials.

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