Fermi arcs, pseudogap, and collective excitations in doped Sr 2 IrO 4 : A generalized fluctuation exchange study
Fermi arcs, pseudogap, and collective excitations in doped Sr 2 IrO 4 : A generalized fluctuation exchange study
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DOI：
10.1103/physrevb.91.165138
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发表时间：
2015-03
影响因子：
3.7
通讯作者：
Hu Wang;Shun-li Yu;Jian-xin Li
中科院分区：
文献类型：
--
作者：
Hu Wang;Shun-li Yu;Jian-xin Li
受最近实验测量的启发，我们研究了掺杂 Sr$_2$IrO$_4$ 中的准粒子光谱和集体激发，其中电子相关性和强自旋轨道耦合 (SOC) 之间存在有趣的相互作用。为了包含 SOC，我们使用 Hugenholtz 图将波动交换 (FLEX) 方法扩展到 SU(2) 对称性可以被破坏的情况。通过使用这种广义的FLEX方法，我们发现在轻微电子掺杂的系统中$(\pi,0)$附近存在弱赝能隙行为，并通过费米面的部分破坏形成相应的费米弧。类似的特征也出现在空穴掺杂系统中，但是费米弧的位置相对于前者旋转了$45^\circ$。这些结果与最近在 Sr$_2$IrO$_4$ 中的角分辨光电子发射光谱一致。我们证明这些异常特征主要是由有效$J_{\text{eff}}=1/2$双峰衍生的同位旋波动引起的。
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 $(\pi,0)$ 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.