Cavity-mediated electron-photon superconductivity
Physical Review Letters American Physical Society 13 (2019) 133602
Abstract:
We investigate electron paring in a two-dimensional electron system mediated by vacuum fluctuations inside a nanoplasmonic terahertz cavity. We show that the structured cavity vacuum can induce long-range attractive interactions between current fluctuations which lead to pairing in generic materials with critical temperatures in the low-kelvin regime for realistic parameters. The induced state is a pair-density wave superconductor which can show a transition from a fully gapped to a partially gapped phase—akin to the pseudogap phase in high-Tc superconductors. Our findings provide a promising tool for engineering intrinsic electron interactions in two-dimensional materials.TeraHertz Josephson Plasmonics: Controlling Supercurrents in Cuprates
Institute of Electrical and Electronics Engineers (IEEE) 00 (2019) 1-1
Magnetic-Field Tuning of Light-Induced Superconductivity in Striped La_{2-x}Ba_{x}CuO_{4}.
Physical review letters 121:26 (2018) 267003
Abstract:
Optical excitation of stripe-ordered La_{2-x}Ba_{x}CuO_{4} has been shown to transiently enhance superconducting tunneling between the CuO_{2} planes. This effect was revealed by a blueshift, or by the appearance of a Josephson plasma resonance in the terahertz-frequency optical properties. Here, we show that this photoinduced state can be strengthened by the application of high external magnetic fields oriented along the c axis. For a 7 T field, we observe up to a tenfold enhancement in the transient interlayer phase correlation length, accompanied by a twofold increase in the relaxation time of the photoinduced state. These observations are highly surprising, since static magnetic fields suppress interlayer Josephson tunneling and stabilize stripe order at equilibrium. We interpret our data as an indication that optically enhanced interlayer coupling in La_{2-x}Ba_{x}CuO_{4} does not originate from a simple optical melting of stripes, as previously hypothesized. Rather, we speculate that the photoinduced state may emerge from activated tunneling between optically excited stripes in adjacent planes.Disorder at the border.
Science (New York, N.Y.) 362:6414 (2018) 525-526
Parametric amplification of optical phonons.
Proceedings of the National Academy of Sciences of the United States of America 115:48 (2018) 12148-12151