Filling-enforced quantum band insulators in spin-orbit coupled crystals.
Filling-enforced quantum band insulators in spin-orbit coupled crystals.
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自旋轨道耦合晶体中的填充强制量子带绝缘体。
DOI：
10.1126/sciadv.1501782
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发表时间：
2016-04
期刊：
影响因子：
13.6
通讯作者：
Vishwanath A
中科院分区：
文献类型：
--
作者：
Po HC;Watanabe H;Zaletel MP;Vishwanath A
量子效应产生了一个带绝缘体，它的电子比任何经典图像所允许的都要少。量子力学的一个早期胜利是根据电子能带的填充解释了金属和绝缘的行为。一个互补的经典绝缘体图将电子描述为占据局域的和对称的Wannier轨道，类似于原子轨道。我们报告的理论发现带绝缘体的电子填充禁止这样的原子描述。我们称它们为填充增强量子带绝缘体（feQBI），因为它们的波函数与量子纠缠的基本程度有关。像拓扑绝缘体一样，它也不允许原子描述，feQBI需要自旋轨道耦合才能实现。然而，它们不一定支持无隙表面态。相反，带拓扑结构反映在非常规填充的绝缘行为中。我们提出了紧密结合的feQBI模型，并表明它们只发生在某些非对称，体心立方晶体。
Quantum effects produce a band insulator with fewer electrons than permitted in any classical picture. An early triumph of quantum mechanics was the explanation of metallic and insulating behavior based on the filling of electronic bands. A complementary, classical picture of insulators depicts electrons as occupying localized and symmetric Wannier orbitals that resemble atomic orbitals. We report the theoretical discovery of band insulators for which electron filling forbids such an atomic description. We refer to them as filling-enforced quantum band insulators (feQBIs) because their wave functions are associated with an essential degree of quantum entanglement. Like topological insulators, which also do not admit an atomic description, feQBIs need spin-orbit coupling for their realization. However, they do not necessarily support gapless surface states. Instead, the band topology is reflected in the insulating behavior at an unconventional filling. We present tight binding models of feQBIs and show that they only occur in certain nonsymmorphic, body-centered cubic crystals.