We evaluate the differential conductance measured in an STM setting at arbitrary electron transmission between STM tip and a 2D superconductor with arbitrary gap structure. Our analytical scattering theory accounts for Andreev reflections, which become prominent at larger transmissions. We show that this provides complementary information about the superconducting gap structure beyond the tunneling density of states, strongly facilitating the ability to extract the gap symmetry and its relation to the underlying crystalline lattice. We use the developed theory to discuss recent experimental results on superconductivity in twisted bilayer graphene.

中文翻译：

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非常规超导体扫描隧道光谱中的 Andreev 反射

我们评估了在 STM 设置中在 STM 尖端和具有任意间隙结构的 2D 超导体之间的任意电子传输下测量的微分电导。我们的分析散射理论解释了 Andreev 反射，这种反射在较大的传输中变得很突出。我们表明，这提供了关于超越状态隧道密度的超导能隙结构的补充信息，极大地促进了提取能隙对称性及其与底层晶格的关系的能力。我们使用发展的理论来讨论最近关于扭曲双层石墨烯超导性的实验结果。