Thermodynamic properties and structural stability of thorium dioxide

doi:10.1088/0953-8984/24/22/225801

CORC > 北京大学 > 工学院

	Thermodynamic properties and structural stability of thorium dioxide
	Lu, Y. ; Yang, Y. ; Zhang, P.
刊名	journal of physics condensed matter
	2012
关键词	AUGMENTED-WAVE METHOD THERMAL-CONDUCTIVITY VIBRATIONAL FREQUENCIES THO2 1ST-PRINCIPLES TEMPERATURE CRYSTALS POINTS UO2
DOI	10.1088/0953-8984/24/22/225801
英文摘要	Using density functional theory (DFT) calculations, we have systematically investigated the thermodynamic properties and structural stabilities of thorium dioxide (ThO2). Based on the calculated phonon dispersion curves, we have calculated the thermal expansion coefficient, bulk modulus, and heat capacities at different temperatures for ThO2 under the quasi-harmonic approximation. All the results are in good agreement with corresponding experiments proving the validity of our methods. Our theoretical studies can aid a clearer understanding of the thermodynamic behaviors of ThO2 at different temperatures. In addition, we have also studied possible defect formations and diffusion behaviors of helium in ThO2, to discuss its structural stability. It is found that in intrinsic ThO2 without any Fermi energy shifts, the interstitial Th-i(4+) defect rather than oxygen or thorium vacancies, interstitial oxygen, or any kinds of Frenkel pairs, is the most probable to form with an energy release of 1.74 eV. However, after upshifting the Fermi energy, the formation of the other defects also becomes possible. Regarding helium diffusion, we find that only through the thorium vacancy can it occur with the small energy barrier of 0.52 eV. Otherwise, helium atoms can hardly incorporate or diffuse in ThO2. Our results indicate that upward shifting of the Fermi energy of ThO2 should be prevented to avoid the formation of thorium vacancies so as to avert helium caused damage.; Physics, Condensed Matter; SCI(E); EI; 0; ARTICLE; 22; 24
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/393346]
专题	工学院
推荐引用方式 GB/T 7714	Lu, Y.,Yang, Y.,Zhang, P.. Thermodynamic properties and structural stability of thorium dioxide[J]. journal of physics condensed matter,2012.
APA	Lu, Y.,Yang, Y.,&Zhang, P..(2012).Thermodynamic properties and structural stability of thorium dioxide.journal of physics condensed matter.
MLA	Lu, Y.,et al."Thermodynamic properties and structural stability of thorium dioxide".journal of physics condensed matter (2012).