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IQIM Postdoctoral and Graduate Student Seminar

Friday, January 21, 2022
11:00am to 12:00pm
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Magnetism and Superconductivity in Crystalline Few-layer Graphene
Haoxin Zhou, IQIM Postdoctoral Scholar, Nadj-Perge Group,

Abstract: Bernal bilayer and rhombohedral trilayer graphene are two crystalline graphene allotropes. Their energy band structures share similar aspects -- both feature van Hove singularities at the band edges that can be enhanced by an electric field. Tunning the Fermi surface close to the van Hove singularities tends to induce instability and therefore novel electronic phenomena. Combining quantum capacitance measurement and electronic transport measurement, we observed a series of gate-tuned phase transitions associated with spontaneous spin- and valley-symmetry breaking in both the bilayer and trilayer systems. More surprisingly, superconductivity was observed in rhombohedral trilayer graphene near some of the phase boundaries and in Bernal bilayer graphene when an in-plane magnetic field is applied. Although the pairing mechanism remains puzzling, we believe our observation introduces significant new constraints to the theory of superconductivity in graphene systems.

Attend by zoom at https://caltech.zoom.us/j/88407627311?pwd=RGx4MlpSUnBLbDJvdE4rS1FHbWZvUT09

For more information, please contact Marcia Brown by phone at 626-395-4013 or by email at [email protected].