ALPHA-GAMMA TRANSITION IN CERIUM IS A MOTT TRANSITION
ALPHA-GAMMA TRANSITION IN CERIUM IS A MOTT TRANSITION
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DOI：
10.1080/14786439808206574
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发表时间：
1974-01-01
影响因子：
1.6
通讯作者：
JOHANSSON, B
中科院分区：
文献类型：
--
作者：
JOHANSSON, B
铈中的α-γ转变被认为是Mott转变。从光谱数据可以得出结论，原子内的相互作用，U，是相当小的似乎已经被认为在过去。这里有人认为，在金属铈中，U仅为几个电子伏特的量级。4f带态宽度的电流能带计算大概是非常不可靠的，并且对离子晶体势的相关效应可能是相当重要的。尽管如此，一些传统的能带计算似乎意味着接近一个电子伏特的宽度，密度适合于铈中致密的α相。关于γ和α铈性质的几个实验事实使我们断言，金属铈不能将其f电子提升到（sd）构型。这是最清楚地看到，从它的内聚能性能，它表明，如果铈达到（sd）4配置，说在a或a相，这将导致一个完全不可接受的行为的四价过渡金属。相反，我们被引导去考虑f电子经历莫特转变，并且鉴于我们在哈伯德图像中的发现，这是最有可能发生的。从这一结论出发，指出了铈和锕系中个别元素的压温相图性质的显著相似性。由此可以得出结论，早期普遍表达的观点，铈，当压缩，成为一个正常的四价过渡，金属是无效的。相反，对轻稀土元素的高压将它们转化为锕系元素。
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,Uis only of the order of a few electron volts. Current band calculations of the width of a 4fband 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 itsfelectron 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)4configuration, 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 thefelectrons 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.