Slave-rotor mean-field theories of strongly correlated systems and the Mott transition in finite dimensions
Slave-rotor mean-field theories of strongly correlated systems and the Mott transition in finite dimensions
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DOI：
10.1103/physrevb.70.035114
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发表时间：
2004-07-01
影响因子：
3.7
通讯作者：
Georges, A
中科院分区：
文献类型：
--
作者：
Florens, S;Georges, A
多轨道哈伯德模型用与局部电荷共轭的量子相变量（“从转子”）和辅助费米子来表示，提供了强关联系统的希尔伯特空间的经济表示。当相位变量被处理在一个本地的平均场的方式，得到类似的结果，动力学平均场理论，即Brinkman-Rice过渡在相称的填充物连同一个“预制”莫特间隙的单粒子态密度。从转子形式主义允许超越本地的描述，并考虑到空间的相关性，以下的超流绝缘体过渡的玻色子系统的类比。我们发现在有限维系统中，短程磁关联抑制了金属-绝缘体转变处有效质量的发散。此外，严格的费米液体相干尺度和莫特间隙之间的能量尺度的分离，发现在本地的图片，持有只有大约在有限的维度，由于存在的低能量集体模式有关的零声。
The multiorbital Hubbard model is expressed in terms of quantum phase variables ("slave rotors") conjugate to the local charge, and of auxiliary fermions, providing an economical representation of the Hilbert space of strongly correlated systems. When the phase variables are treated in a local mean-field manner, similar results to the dynamical mean-field theory are obtained, namely a Brinkman-Rice transition at commensurate fillings together with a "preformed" Mott gap in the single-particle density of states. The slave-rotor formalism allows to go beyond the local description and take into account spatial correlations, following an analogy to the superfluid-insulator transition of bosonic systems. We find that the divergence of the effective mass at the metal-insulator transition is suppressed by short range magnetic correlations in finite-dimensional systems. Furthermore, the strict separation of energy scales between the Fermi-liquid coherence scale and the Mott gap, found in the local picture, holds only approximately in finite dimensions, due to the existence of low-energy collective modes related to zero-sound.