论文标题
在FESE中用硫取代的异常带分裂和超导间隙演变
Unusual band splitting and superconducting gap evolution with sulfur substitution in FeSe
论文作者
论文摘要
对FESE $ _ {1-X} $ s $ _x $（x = 0、0.04和0.08）超导体进行了高分辨率角度分辨的光发射测量。在所有硫取代的样品中都鉴定出了超高的能量分辨率为0.4 meV，在布里鲁因区中心附近不寻常的两个孔带，这可能是由于额外的对称性破裂的结果。此外，在两个孔带中都证明了高度各向异性超导差距具有限制性节点。我们发现，外孔带上的较大的超导间隙线性降低至列明转变温度，而内部孔的间隙几乎独立于S-固定。我们的观察结果强烈表明，超导差距随着增强性而增加，尽管超导过渡温度不仅受配对强度的控制，而且表现出对FESE家族中理论的强烈限制。
High-resolution angle-resolved photoemission measurements were taken on FeSe$_{1-x}$S$_x$ (x=0, 0.04, and 0.08) superconductors. With an ultrahigh energy resolution of 0.4 meV, unusual two hole bands near the Brillouin-zone center, which was possibly a result of additional symmetry breaking, were identified in all the sulfur-substituted samples. In addition, in both of the hole bands highly anisotropic superconducting gaps with resolution limited nodes were evidenced. We find that the larger superconducting gap on the outer hole band is reduced linearly to the nematic transition temperature while the gap on the inner hole is nearly S-substitution independent. Our observations strongly suggest that the superconducting gap increases with enhanced nematicity although the superconducting transition temperature is not only governed by the pairing strength, demonstrating strong constraints on theories in the FeSe family.
