Anomalous crossed Andreev reflection in nodal line semimetals

In accordance with the trajectory of the reflected hole, local Andreev reflection (AR) in three dimensions can be classified into three distinct types, namely retro AR, specular AR, and anomalous AR, which collectively constitute a complete set of local AR. Expanding this classification to crossed Andreev reflection (CAR), we categorize it into forward CAR, negative CAR, and anomalous CAR, which involve the reversal of zero, two, and one lateral velocity components, respectively, with respect to the incident electron. Forward CAR and negative CAR are commonly observed in materials with spherical Fermi surfaces. In this work, we investigate the CAR in a nodal line semimetal-superconductor-nodal line semimetal junction, and find that the presence of a torus-shaped Fermi surface in nodal line semimetals leads to the occurrence of rare anomalous CAR. Notably, in the presence of the interface barriers, the anomalous CAR is found to dominate nonlocal transport within a specific energy range. We show that the anomalous CAR visibly manifests itself as a ridge structure in the spatially resolved conductance, serving as a distinct signature of this peculiar anomalous CAR phenomenon.