Layer-resolved electronic behavior in a Kondo lattice system, CeAgAs₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spectroscopy

Background:

• CeAgAs2 is an orthorhombic variant of the HfCuSi2 structure.
• It exhibits an antiferromagnetic ground state, Kondo-like resistivity upturn, and magnetic moment compensation at low temperatures.

Purpose of the Study:

• To investigate the electronic structure of the antiferromagnetic Kondo lattice system CeAgAs2.
• To understand the surface-bulk electronic differences and the role of hybridization and electron correlation.

Main Methods:

• Hard X-ray photoemission spectroscopy (HAXPES) was employed.
• Depth-resolved measurements were performed at varying photon energies.

Main Results:

• Significant surface-bulk differences were observed in As and Ce core-level spectra.
• Strong Ce-As hybridization and electron correlation were identified.
• Temperature-dependent changes in spectral weight transfer and Fermi level intensity were consistent with Kondo behavior.

Conclusions:

• The study reveals distinct electronic structures between the surface and bulk of CeAgAs2.
• Complex interplay of intra- and inter-layer covalency and electron correlation influences the electronic properties.
• These findings provide insights into the novel Kondo lattice system CeAgAs2.