Long range order and two-fluid behavior in heavy electron materials.

Area of Science:

• Condensed matter physics
• Quantum materials
• Emergent phenomena

Background:

• Heavy electron systems exhibit complex electronic states arising from the hybridization of localized f-electrons with conduction electrons.
• The Kondo liquid is a key emergent state characterized by universal properties, often coexisting with local moment behavior before ordering.
• NMR Knight shift is a sensitive probe of the electronic environment and hybridization dynamics in these materials.

Purpose of the Study:

• To investigate the two-fluid behavior and the origins of long-range order in heavy electron materials.
• To extend NMR Knight shift measurements to URu(2)Si(2), CeIrIn(5), and CeRhIn(5) to probe their ground states.
• To differentiate between local moment physics and hybridization effects in the formation of ordered states.

Main Methods:

• Nuclear Magnetic Resonance (NMR) Knight shift measurements.
• Experimental investigation of heavy fermion compounds URu(2)Si(2), CeIrIn(5), and CeRhIn(5).
• Analysis of spectral weight transfer and electronic state evolution with temperature.

Main Results:

• In CeRhIn(5), antiferromagnetic order is preceded by Kondo liquid relocalization, indicating a local moment origin.
• In URu(2)Si(2), the hidden order emerges directly from the Kondo liquid, independent of local moment physics.
• NMR Knight shift data supports a strong coupling between ground state properties and Kondo lattice hybridization.

Conclusions:

• The ground state of heavy electron materials is intimately linked to the hybridization within the Kondo lattice.
• NMR Knight shift measurements provide crucial insights into the microscopic origins of different ordering phenomena.
• The findings align with theoretical models describing the interplay of hybridization and electronic correlations in heavy fermion systems.