Sequential localization of a complex electron fluid
Sequential localization of a complex electron fluid
复制标题
复杂电子流体的顺序定位
DOI：
10.1073/pnas.1908101116
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发表时间：
2019-09-03
影响因子：
11.1
通讯作者：
Paschen, Silke
中科院分区：
文献类型：
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作者：
Martelli, Valentina;Cai, Ang;Paschen, Silke
意义许多最迷人和积极研究的材料类主机强相关电子。他们的理解是具有挑战性的，因为强相关性导致电子的多个自由度缠绕，如自旋，轨道和电荷。这种复杂性无处不在，是许多丰富属性的基础。那么问题就在于，是否存在一种通用的组织原则，可以简化描述。在这里，通过研究一个原型材料与包绕自旋和轨道的自由度和相关的理论模型，我们已经证明了相关驱动的电子定域-离域作为这样一个原则。它是按顺序发生的，每次只涉及一个量子数，从而破译了各个自由度的作用。具有新功能的复杂和相关量子系统通常涉及电子自由度。在这样的材料中，出现了非常不寻常的性质，可能是电子局域化的结果。在这里，一个由自旋和轨道控制的立方重费米子金属被选为这个物理学的模型系统。它的性质被发现起源于令人惊讶的简单的低能量行为，与2个不同的本地化转换驱动的一个自由度的时间。这个结果是出乎意料的，但我们能够通过提出SU（4）自旋轨道耦合近藤纠缠的顺序破坏的概念来理解它。我们的研究结果表明，电子局域化作为一个统一的框架，强相关的材料，并建议如何利用多个自由度的量子工程。
Significance Many of the most fascinating and actively investigated materials classes host strongly correlated electrons. Their understanding is challenging because the strong correlations cause entwining of multiple degrees of freedom of an electron, such as spin, orbital, and charge. This complexity is ubiquitous and underlies many of the rich properties. The question then is whether there are universal organizing principles that provide simplicity to the description. Here, by studying a prototype material with entwined spin and orbital degrees of freedom and a theoretical model pertinent to it, we have demonstrated correlation-driven electron localization–delocalization as such a principle. It happens sequentially, involving a single quantum number at a time, thus deciphering the roles of the individual degrees of freedom. Complex and correlated quantum systems with promise for new functionality often involve entwined electronic degrees of freedom. In such materials, highly unusual properties emerge and could be the result of electron localization. Here, a cubic heavy fermion metal governed by spins and orbitals is chosen as a model system for this physics. Its properties are found to originate from surprisingly simple low-energy behavior, with 2 distinct localization transitions driven by a single degree of freedom at a time. This result is unexpected, but we are able to understand it by advancing the notion of sequential destruction of an SU(4) spin–orbital-coupled Kondo entanglement. Our results implicate electron localization as a unified framework for strongly correlated materials and suggest ways to exploit multiple degrees of freedom for quantum engineering.