Savrasov S Y, Kotliar G, Abrahams E
Department of Physics and Astronomy and Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854-8019, USA.
Nature. 2001 Apr 12;410(6830):793-5. doi: 10.1038/35071035.
Given the practical importance of metallic plutonium, there is considerable interest in understanding its fundamental properties. Plutonium undergoes a 25 per cent increase in volume when transformed from its alpha-phase (which is stable below 400 K) to the delta-phase (stable at around 600 K), an effect that is crucial for issues of long-term storage and disposal. It has long been suspected that this unique property is a consequence of the special location of plutonium in the periodic table, on the border between the light and heavy actinides-here, electron wave-particle duality (or itinerant versus localized behaviour) is important. This situation has resisted previous theoretical treatment. Here we report an electronic structure method, based on dynamical mean-field theory, that enables interpolation between the band-like and atomic-like behaviour of the electron. Our approach enables us to study the phase diagram of plutonium, by providing access to the energetics and one-electron spectra of strongly correlated systems. We explain the origin of the volume expansion between the alpha- and delta-phases, predict the existence of a strong quasiparticle peak near the Fermi level and give a new viewpoint on the physics of plutonium, in which the alpha- and delta-phases are on opposite sides of the interaction-driven localization-delocalization transition.
鉴于金属钚的实际重要性，人们对了解其基本性质有着浓厚的兴趣。钚从其α相（在400K以下稳定）转变为δ相（在600K左右稳定）时，体积会增加25%，这一效应对于长期储存和处置问题至关重要。长期以来，人们一直怀疑这种独特的性质是钚在元素周期表中特殊位置的结果，它位于轻锕系元素和重锕系元素之间的边界上——在这里，电子波粒二象性（即巡游与局域行为）很重要。这种情况一直难以用以往的理论进行处理。在此，我们报告一种基于动态平均场理论的电子结构方法，该方法能够在电子的类能带行为和类原子行为之间进行插值。我们的方法通过提供对强关联系统的能量学和单电子光谱的访问，使我们能够研究钚的相图。我们解释了α相和δ相之间体积膨胀的起源，预测了费米能级附近存在一个强准粒子峰，并给出了关于钚物理学的新观点，其中α相和δ相处于相互作用驱动的局域化 - 非局域化转变的相反两侧。
