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arXiv 1406.5271cond-mat.str-el
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自旋轨道密度波:适用于URu2Si2隐序态的物质新相

Spin-orbit density wave: A new phase of matter applicable to the hidden order state of URu2Si2

Tanmoy Das

摘要:

我们提供了一个简短的回顾和详细的分析的自旋轨道密度波(SODW),提出了一个可能的解释的“隐藏顺序”阶段的URu 2Si 2。由于轨道间库仑相互作用和自旋轨道耦合(SOC)之间的相互作用,在这个化合物中,SODW被证明是由两个自旋轨道分裂带之间的费米面嵌套不稳定性。推导了包含单粒子自组织和双粒子自组织的有效低能哈密顿量,并采用基于能带结构的密度泛函理论(DFT)输入进行了数值计算.计算得到的能隙准粒子谱、熵损失谱和自旋激发谱与实验符合较好。有趣的是,尽管SODW支配动态自旋激发的事实,静态磁矩计算为零,由于时间反演不变性的SOC施加。因此,SODW可以被破坏,即使在零温度下的有限磁场。我们对量子临界点位置的估计接近于实验值Bc ~ 35 T。最后,我们将SODW的思想扩展到其他SOC系统,包括铱氧化物(铱酸盐)和二维电子系统,如BiAg 2表面和LaAlO 3/SrTiO 3界面。我们显示出准粒子间隙,减少预先存在的磁矩,大的磁阻等线索,在这些系统中,可以解释一致的SODW理论。

英文摘要:

We provide a brief review and detailed analysis of the spin-orbit density wave (SODW), proposed as a possible explanation to the `hidden order' phase of URu2Si2. Due to the interplay between inter-orbital Coulomb interaction and spin-orbit coupling (SOC) in this compound, the SODW is shown to arise from Fermi surface nesting instability between two spin-orbit split bands. An effective low-energy Hamiltonian including single-particle SOC and two-particle SODW is derived, while numerical results are calculated by using density-functional theory (DFT) based band structure input. Computed gapped quasiparticle spectrum, entropy loss and spin-excitation spectrum are in detailed agreement with experiments. Interestingly, despite the fact that SODW governs dynamical spin-excitations, the static magnetic moment is calculated to be zero, owing to the time-reversal invariance imposed by SOC. As a consequence, SODW can be destroyed by finite magnetic field even at zero temperature. Our estimation of the location of the quantum critical point is close to the experimental value of Bc ~ 35 T. Finally, we extend the idea of SODW to other SOC systems including iridium oxides (iridates) and two-dimensional electronic systems such as BiAg2 surface and LaAlO3/SrTiO3 interface. We show hints of quasiparticle gapping, reduction of preexisting magnetic moment, large magneto-resistance etc. in these systems which can be explained consistently within the SODW theory.

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