scholarly journals Prediction of 2D ferromagnetism and monovalent europium ions in the EuBr/graphene heterojunctions

2021 ◽  
Author(s):  
Haoyi Tan ◽  
Guangcun Shan ◽  
Gianfranco Pacchioni
Keyword(s):  
Density Functional Theory ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Valence States ◽  
Magnetic Modification ◽  
Modification Of Materials ◽  
The Rare Earth

Europium, one of the rare earth elements, exhibits +2 and +3 valence states and has been widely used for magnetic modification of materials. Based on density functional theory calculations, we...

scholarly journals Origin of enhanced chemical precompression in cerium hydride $$\hbox {CeH}_{{9}}$$

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hyunsoo Jeon ◽  
Chongze Wang ◽  
Seho Yi ◽  
Jun-Hyung Cho
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Metal ◽  
Density Functional ◽  
Metal Hydrides ◽  
Earth Metal ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Valence States

Abstract The rare-earth metal hydrides with clathrate structures have been highly attractive because of their promising high-$$T_{\rm{c}}$$ T c superconductivity at high pressure. Recently, cerium hydride $$\hbox {CeH}_9$$ CeH 9 composed of Ce-encapsulated clathrate H cages was synthesized at much lower pressures of 80–100 GPa, compared to other experimentally synthesized rare-earth hydrides such as $$\hbox {LaH}_{{10}}$$ LaH 10 and $$\hbox {YH}_6$$ YH 6 . Based on density-functional theory calculations, we find that the Ce 5p semicore and 4f/5d valence states strongly hybridize with the H 1s state, while a transfer of electrons occurs from Ce to H atoms. Further, we reveal that the delocalized nature of Ce 4f electrons plays an important role in the chemical precompression of clathrate H cages. Our findings not only suggest that the bonding nature between the Ce atoms and H cages is characterized as a mixture of ionic and covalent, but also have important implications for understanding the origin of enhanced chemical precompression that results in the lower pressures required for the synthesis of $$\hbox {CeH}_9$$ CeH 9 .

Is a Non-Transition Element Nitride Ferromagnet Ever Achievable? Indication of the N-N Pairing Instability

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition Element ◽  
Density Functional Theory Calculations ◽  
Functional Theory

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.

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