Condensed Matter Physics: Topological Heterostructures
Technical Report,15 Jul 2016,14 Feb 2018
College of William and Mary Williamsburg United States
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During the course of the project we have developed the theory and the numerical approaches to describe junctions formed by superconductors SCs and nodal ring Weyl semimetals WSMs. In particular, we have focused on developing the theoretical and numerical tools to obtain the Josephson current in SC-WSM-SC junctions. One of the key property of nodal ring WSMs is to have surface states, so called drumhead states, with an almost flat dispersion i.e. with a very large effective mass. Such surface states are extremely interestingbecause they are a clear signature of the nodal ring character of the WSM, they are expected to give rise to anomalous transport properties, and be susceptible to strong correlation effects. We have carefully characterized the nodal rings and the corresponding bands. In real systems it is expected that the drumhead states will have some finite dispersion. We showed how SC-WSM junctions can be used to detect the effective mass flatness of the drumhead states. Our results suggest that a measurement of the Andreev reflection can be used to detect thepolarization and the effective mass of drumhead states. We then developed the approach to calculate the Josephson current for SC-WSM-SC junctions.
- Electricity and Magnetism
- Atomic and Molecular Physics and Spectroscopy