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Gyenis A, Feldman BE, Randeria MT, Peterson GA, Bauer ED, Aynajian P, Yazdani A. Visualizing heavy fermion confinement and Pauli-limited superconductivity in layered CeCoIn 5. Nat Commun 2018; 9:549. [PMID: 29416021 PMCID: PMC5803268 DOI: 10.1038/s41467-018-02841-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/03/2018] [Indexed: 11/09/2022] Open
Abstract
Layered material structures play a key role in enhancing electron–electron interactions to create correlated metallic phases that can transform into unconventional superconducting states. The quasi-two-dimensional electronic properties of such compounds are often inferred indirectly through examination of bulk properties. Here we use scanning tunneling microscopy to directly probe in cross-section the quasi-two-dimensional electronic states of the heavy fermion superconductor CeCoIn5. Our measurements reveal the strong confined nature of quasiparticles, anisotropy of tunneling characteristics, and layer-by-layer modulated behavior of the precursor pseudogap gap phase. In the interlayer coupled superconducting state, the orientation of line defects relative to the d-wave order parameter determines whether in-gap states form due to scattering. Spectroscopic imaging of the anisotropic magnetic vortex cores directly characterizes the short interlayer superconducting coherence length and shows an electronic phase separation near the upper critical in-plane magnetic field, consistent with a Pauli-limited first-order phase transition into a pseudogap phase. The electronic properties along the out-of-plane direction of layered materials are often inferred indirectly. Here, Gyenis et al. directly probe in cross-section the quasi-two-dimensional correlated electronic states of the heavy fermion superconductor CeCoIn5.
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Affiliation(s)
- András Gyenis
- Joseph Henry Laboratories of Physics, Department of Physics, Princeton University, Princeton, NJ, 08544, USA.,Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Benjamin E Feldman
- Joseph Henry Laboratories of Physics, Department of Physics, Princeton University, Princeton, NJ, 08544, USA.,Department of Physics, Stanford University, Stanford, CA, 94305, USA
| | - Mallika T Randeria
- Joseph Henry Laboratories of Physics, Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Gabriel A Peterson
- Joseph Henry Laboratories of Physics, Department of Physics, Princeton University, Princeton, NJ, 08544, USA.,National Institute of Standards and Technology, Boulder, CO, 80305, USA
| | - Eric D Bauer
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Pegor Aynajian
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY, 13902, USA
| | - Ali Yazdani
- Joseph Henry Laboratories of Physics, Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
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