Topological superconductivity realizations in 2D material system
ORAL · Invited
Abstract
As two indistinguishable elementary particles interchange their positions, a fundamental property of their nature is revealed, their exchange statistics. This property gives rise to the Pauli exclusion principle of fermions, or the Bose-Einstein condensation of bosons. In the field of condensed-matter physics, governed by many-body interactions, novel exchange statistics may manifest in the emergence of different quantum phases. Of particular interest is the non-abelian exchange statistics, emanating from unconventional phases featuring topological superconductivity.
In this talk I will introduce two main examples aimed at topological superconductivity realizations in 2D material systems. The first example is based on the fractional quantum Hall effect (FQHE). Here, we use hBN-encapsulated monolayer graphene with top and bottom graphite gates to electrostatically define tunable Fabry-Pérot interferometers. Screening in the van der Waals heterostructure suppresses charging effects, yielding highly visible Aharonov-Bohm interference of integer quantum Hall edges [1]. This experiment opens up new possibilities for studies of non-abelian anyons in exotic fractional states. In the second example, I will present a realization where superconductivity and robust FQHE coexist. Here, by constructing high-quality graphene-based van der Waals devices with narrow superconducting niobium nitride (NbN) electrodes, we find crossed Andreev reflection across a superconductor separating two FQH edges. These hybrid SC-FQHE heterostructures are of special interest since they expect to manifest higher-order non-abelian states [2].
[1] Ronen Y., Werkmeister T., Najafabadi D., Pierce A. T., Anderson L. E., Shin Y. J., Lee S. Y., Lee Y. H., Johnson B., Watanabe K., Taniguchi T., Yacoby A. & Kim P. Nature Nanotechnology 16, 563-569 (2021)
[2] Gül Ö., Ronen Y., Lee S. Y., Shapourian H., Zauberman J., Lee Y. H., Watanabe K., Taniguchi T., Vishwanath A., Yacoby A. & Kim P. Physical Review X. 12, 2, 021057 (2022)
In this talk I will introduce two main examples aimed at topological superconductivity realizations in 2D material systems. The first example is based on the fractional quantum Hall effect (FQHE). Here, we use hBN-encapsulated monolayer graphene with top and bottom graphite gates to electrostatically define tunable Fabry-Pérot interferometers. Screening in the van der Waals heterostructure suppresses charging effects, yielding highly visible Aharonov-Bohm interference of integer quantum Hall edges [1]. This experiment opens up new possibilities for studies of non-abelian anyons in exotic fractional states. In the second example, I will present a realization where superconductivity and robust FQHE coexist. Here, by constructing high-quality graphene-based van der Waals devices with narrow superconducting niobium nitride (NbN) electrodes, we find crossed Andreev reflection across a superconductor separating two FQH edges. These hybrid SC-FQHE heterostructures are of special interest since they expect to manifest higher-order non-abelian states [2].
[1] Ronen Y., Werkmeister T., Najafabadi D., Pierce A. T., Anderson L. E., Shin Y. J., Lee S. Y., Lee Y. H., Johnson B., Watanabe K., Taniguchi T., Yacoby A. & Kim P. Nature Nanotechnology 16, 563-569 (2021)
[2] Gül Ö., Ronen Y., Lee S. Y., Shapourian H., Zauberman J., Lee Y. H., Watanabe K., Taniguchi T., Vishwanath A., Yacoby A. & Kim P. Physical Review X. 12, 2, 021057 (2022)
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Publication: [1] Ronen Y., Werkmeister T., Najafabadi D., Pierce A. T., Anderson L. E., Shin Y. J., Lee S. Y., Lee Y. H., Johnson B., Watanabe K., Taniguchi T., Yacoby A. & Kim P. Nature Nanotechnology 16, 563-569 (2021)<br>[2] Gül Ö., Ronen Y., Lee S. Y., Shapourian H., Zauberman J., Lee Y. H., Watanabe K., Taniguchi T., Vishwanath A., Yacoby A. & Kim P. Physical Review X. 12, 2, 021057 (2022)
Presenters
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Yuval Ronen
Weizmann Institute of Science, Harvard University, Weizmann Institute of Science
Authors
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Yuval Ronen
Weizmann Institute of Science, Harvard University, Weizmann Institute of Science