Unconventional superconductivity and the electronic structure of 4Hb-TaS2 |
TYPE | Student Seminar |
Speaker: | Avior Almoalem |
Organizer: | Ari Turner |
Date: | 23.08.2022 |
Time: | 14:30 - 15:30 |
Location: | Lidow Nathan Rosen (300) |
Abstract: | In transition-metal dichalcogenides the proximity between layers of broken inversion symmetry with strong spin–orbit coupling and layers of strongly correlated electrons provides a platform for studies of newly discovered phases.
Anomalous magnetic memory effect, topological superconductivity and broken time reversal symmetry are among the novel phases found and measured in 4Hb-TaS2. Among other phases believed to exist in this material is chiral-triplet superconductivity, which could provide a platform for realizing Majorana edge modes. However, so far no clear evidence has been shown for such pairing.
We present, using the Little-Parks experiment, evidence for an unconventional order parameter in 4Hb-TaS2. We find a pi shift in the Little-Parks oscillations, an unambiguous indication of a two-component order parameter.
In addition, we find that in the presence of an in-plane magnetic field the transition temperature increases upon the application of an out-of-plane field as expected for certain chiral superconductors. Furthermore, using ARPES and DFT we show that the band structure of 4Hb-TaS2 is substantially different from that of the constituents 2H-TaS2 and 1T-TaS2. We show that the proximity between layers of strongly correlated electron systems, including superconductivity and a depleted Mott insulator, can bring about other intricate phases such as those in 4Hb-TaS2.
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