Electronic structure and the Fermi surface of UBe

Maehira, Takahiro; Higashitani, Atsushi*; Higuchi, Masahiko*; Yasuhara, Hiroshi*; Hasegawa, Akira*

Physica B; Condensed Matter, 312-313(1-4), p.103 - 105, 2002/03

https://doi.org/10.1016/S0921-4526(01)01073-0

UBe is a typical heavy-fermion superconductor compound. The lowtemperature electronic specific heat coefficient has the anomalous large value, =1.1J/Kmol, which is the largest among the heavy fermion uranium compounds. It also becomes the superconductor below T=0.85K. Therefore, UBe is an important material as a strongly correlated electron system, and it is necessary to study from both sides of the theory and the experiment. The measurement suggests that the Fermi surface of UBe may consist of small sheets. The energy band structure and the Fermi surface for UBe are calculated by the relativistic linear APW method.

A study on properties of uranium oxide using band theory

Tejima, Shogo

JNC TN8400 2000-029, 54 Pages, 2000/10

JNC-TN8400-2000-029.pdf:1.32MB

This report describes the study done by the author as a postdoctoral research associate at Japan Nuclear Cycle Development Institute. This report is divided into three parts: construction of a relativistic band calculation formalism based on the density functional theory, using this method, investigation of the electrical properties for ferromagnetic UGe and antiferromagnetic UO. (1)A relativistic band calculation (RBC) method. Band calculations for the s, p, and d electric structure have been developed well in the practical application and theoretical study. But band calculation method treating magnetic 5f electrons as actinide compounds are complicated and needed relativistic approach, so it is behind with the study of the 5f system. In this study we construct the relativistic band calculationformalism valid for magnetic 5f electrons. (2)Electric properties of UGe. The actinide compounds UGe is ferromagnetic, so the theoretical analysis is not well yet. The electric structure and fermi surface of UGe are analyzed using the RBC. The theoretical results show that UGe is heavy electron with the 5f character and are agreement with experimental one. (3)Electric structure of nuclear fuel UO. It is important to understand the mechanism of the thermal conductivity of nuclear fuel as antiferromagnetic UO. The UO band calculation reflecting the thermal properties, into account of relativistic effect, have not done yes. So using the RBC the detailed electric structure of UO are obtained.