Researchers have made a groundbreaking discovery in the field of heavy-fermion metals, with the identification of a two-dimensional heavy fermion state in the van der Waals metal CeSiI. This finding opens up new possibilities for controlling quantum phases in these materials, which are known for their emergent quantum behaviors driven by electronic interactions.
The study, led by Victoria A. Posey and her team, provides comprehensive evidence of an antiferromagnetically ordered heavy-fermion ground state in CeSiI. Unlike traditional intermetallic heavy-fermion compounds with three-dimensional structures, CeSiI is composed of two-dimensional metallic sheets held together by weak interlayer van der Waals interactions, allowing for control over its physical dimension through exfoliation.
The quasi-2D electronic structure of CeSiI enables the emergence of coherent hybridization of f and conduction electrons at low temperatures, as supported by various spectroscopic and thermodynamic measurements. Furthermore, electrical transport measurements on few-layer flakes demonstrate heavy-fermion behavior and magnetic order even in the ultra-thin regime.
This discovery establishes CeSiI and related materials as a unique platform for studying dimensionally confined heavy fermions in bulk crystals. It also opens up opportunities for employing 2D device fabrication techniques and van der Waals heterostructures to manipulate the interplay between Kondo screening, magnetic order, and proximity effects.
