Spin and charge transport in topological nodal-line semimetals

We study transport properties of topological Weyl nodal-line semimetals (NLSs). Starting from a minimal lattice model with a single nodal loop, and by focusing on a normal metal-NLS-normal metal junction, we investigate the dependence of the novel transport behavior on the orientation of the nodal loop. When the loop is parallel to the junction interfaces, the transmitted current is found to be nearly fully spin polarized. Correspondingly, there exists a spin orientation along which the incident electrons would be totally reflected. An unusual resonance of half transmission with the participation of surface states also occurs for a pair of incident electrons with opposite spin orientations. All these phenomena have been shown to originate from the existence of a single forward-propagating mode in the NLS of the junction and argued to survive in more generic multiband Weyl NLSs.