Superconducting gap symmetry from Bogoliubov quasiparticle interference analysis on Sr2RuO4
Superconducting gap symmetry from Bogoliubov quasiparticle interference analysis on Sr2RuO4
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DOI：
10.1103/physrevb.107.144505
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发表时间：
2021-09
影响因子：
3.7
通讯作者：
S. Bhattacharyya;A. Kreisel;X. Kong;T. Berlijn;A. T. Rømer;B. M. Andersen;P. Hirschfeld
中科院分区：
文献类型：
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作者：
S. Bhattacharyya;A. Kreisel;X. Kong;T. Berlijn;A. T. Rømer;B. M. Andersen;P. Hirschfeld
近年来，{Sr}$_2${RuO}$_4$中超导序参量的性质引起了人们极大的兴趣。由于超导带隙非常小，高分辨率的方法，如扫描隧道光谱可能是最好的机会，直接解决差距对称性。最近，Bogoliubov准粒子干涉成像（BQPI）实验表明，d_{x^2-y^2}$能隙对称性适合于{Sr}$2 ${RuO}$4 $。在这项工作中，我们使用一种材料特定的理论方法的基础上的Wannier函数的表面的{Sr}$_2${RuO}$_4$计算的连续态密度在扫描隧道显微镜实验中检测到。我们研究了几个不同的建议间隙顺序参数，并计算预期的BQPI模式为每种情况下。与现有的实验数据相比，我们的结果表明，一个$s '+ id_{xy}$间隙序参数是最可能的状态，但测量的BQPI图案仍然显示的功能，目前正在讨论的任何状态的理论无法解释。
The nature of the superconducting order parameter in {Sr}$_2${RuO}$_4$ has generated intense interest in recent years. Since the superconducting gap is very small, high resolution methods such as scanning tunneling spectroscopy might be the best chance to directly resolve the gap symmetry. Recently, a Bogoliubov quasiparticle interference imaging (BQPI) experiment has suggested that the $d_{x^2-y^2}$ gap symmetry is appropriate for {Sr}$_2${RuO}$_4$. In this work, we use a material-specific theoretical approach based on Wannier functions of the surface of {Sr}$_2${RuO}$_4$ to calculate the continuum density of states as detected in scanning tunneling microscopy experiments. We examine several different proposed gap order parameters, and calculate the expected BQPI pattern for each case. Comparing to the available experimental data, our results suggest that a $s'+id_{xy}$ gap order parameter is the most probable state, but the measured BQPI patterns still display features unaccounted for by the theory for any of the states currently under discussion.