arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1503.02544cond-mat.str-elcond-mat.mtrl-sci
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掺杂Sr2IrO4中的费米弧、赝能隙和集体激发:广义涨落交换研究

Fermi arcs, pseudogap and collective excitations in doped Sr2IrO4: A generalized fluctuation exchange study

Hu Wang, Shun-Li Yu, Jian-Xin Li

摘要:

基于最近的实验测量,我们研究了掺杂Sr $_2$ IrO $_4$的准粒子谱和集体激发,其中电子关联和强自旋轨道耦合(SOC)之间存在有趣的相互作用.为了包含SOC,我们使用Hugenholtz图将涨落交换(FLEX)方法扩展到SU(2)对称性可以破缺的情况。利用这种广义FLEX方法,我们发现在微电子掺杂系统中,在$(π,0)$附近存在一个弱的赝能隙行为,费米面的部分破坏形成了相应的费米弧.类似的特征也出现在空穴掺杂系统中,然而,费米弧的位置相对于前者旋转$45^\circ$。这些结果与Sr $_2$ IrO $_4$的角分辨光电子能谱一致。我们证明了这些反常特征主要是由有效$J_{\text{eff}}=1/2$二重态的同位旋涨落引起的。

英文摘要:

Motivated by recent experimental measurements, we study the quasiparticle spectra and the collective excitations in doped Sr$_2$IrO$_4$, in which the interesting interplay between the electronic correlations and strong spin-orbital coupling (SOC) exists. To include the SOC, we use the Hugenholtz diagrams to extend the fluctuation exchange (FLEX) approach to the case where the SU(2) symmetry can be broken. By using this generalized FLEX method, we find a weak pseudogap behavior near $(π,0)$ in the slightly electron-doped system, with the corresponding Fermi arc formed by the partial destruction of Fermi surface. Similar features also appear in the hole-doped system, however, the position of the Fermi arc is rotated $45^\circ$ with respect to the former. These results are consistent with the recent angle-resolved photoemission spectra in Sr$_2$IrO$_4$. We demonstrate that these anomalous features are mainly caused by the isospin fluctuations derived from the effective $J_{\text{eff}}=1/2$ doublet.

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