The α-γ transition in cerium is a Mott transitionстатья из журнала
Аннотация: Abstract The α-γ transition in cerium is considered as a Mott transition. From spectroscopic data it is concluded that the intra-atomic interaction, U, is considerably smaller than seems to have been believed in the past. Here it is argued that in metallic cerium, U is only of the order of a few electron volts. Current band calculations of the width of a 4f band state are presumably very unreliable, and correlation effects on the ionic crystal potential are probably of considerable importance. Still, some conventional band calculations seem to imply a width of nearly one electron volt for densities appropriate for the dense a phase in cerium. Several experimental facts on the properties of γ and α cerium lead us to assert that metallic cerium cannot promote its f electron into the (sd) configuration. This is most clearly seen from its cohesive energy properties, and it is shown that if cerium were to attain an (sd)4 configuration, say in the a or a phase, this would lead to a totally unacceptable behaviour of a tetravalent transition metal. Instead we are led to consider the f electrons as undergoing a Mott transition and in view of our findings within the Hubbard picture this is a most likely occurrence. From this conclusion, the remarkable similarity of the properties of the pressure-temperature phase diagram of cerium and individual elements in the actinide series is pointed out. From this it is concluded that the earlier commonly expressed view that cerium, when compressed, becomes a normal tetravalent transition, metal is invalid. Instead, high pressure on light rare earths element rather converts them into actinide type elements.
Год издания: 1974
Авторы: Börje Johansson
Издательство: Taylor & Francis
Источник: Philosophical magazine
Ключевые слова: Rare-earth and actinide compounds, High-pressure geophysics and materials, Advanced Chemical Physics Studies
Открытый доступ: closed
Том: 30
Выпуск: 3
Страницы: 469–482