Quantum well states in fractured crystals of the heavy fermion material CeCoIn${}_5$

Abstract

Quantum well states appear in metallic thin films due to the confinement of the wave function by the film interfaces. Using angle-resolved photoemission spectroscopy, we unexpectedly observe quantum well states in fractured single crystals of CeCoIn${}_5$. We confirm that confinement occurs by showing that these states' binding energies are photon-energy independent and are well described with a phase accumulation model, commonly applied to quantum well states in thin films. This indicates that atomically flat thin films can be formed by fracturing hard single crystals. For the two samples studied, our observations are explained by free-standing flakes with thicknesses of 206 and 101 Å. We extend our analysis to extract bulk properties of CeCoIn${}_5$. Specifically, we obtain the dispersion of a three-dimensional band near the zone center along in-plane and out-of-plane momenta. We establish part of its Fermi surface, which corresponds to a hole pocket centered at $\Gamma$. We also reveal a change of its dispersion with temperature, a signature that may be caused by the Kondo hybridization.

11 pages, 8 figures

References in corpus (4)

• A precise method for visualizing dispersive features in image plots
• The electronic structure of CeCoIn5 from angle-resolved photoemission spectroscopy II: Hybridization effects
• Low work function in the 122-family of iron-based superconductors
• Quantum well states in fractured crystals of the heavy fermion material CeCoIn${}_5$

Cited by in corpus (5)

• Distinct band reconstructions in kagome superconductor CsV${}_3$Sb${}_5$
• Quantum well states in fractured crystals of the heavy fermion material CeCoIn${}_5$
• Direct Visualization and Manipulation of Tunable Quantum Well State in Semiconducting Nb2SiTe4
• Observation of Electride-like $s$ States Coexisting with Correlated $d$ Electrons in NdNiO${}_2$
• Evidence for freezing of charge degrees of freedom across a critical point in CeCoIn${}_5$