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Kondo lattice heavy fermion behavior in CeRh2Ga2
V K Anand1,2, D T Adroja2,3, A Bhattacharyya2,3
1Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner Platz 1, D-14109 Berlin, Germany.
Summary
The intermetallic compound CeRh2Ga2 exhibits Kondo lattice behavior and a metallic ground state, classifying it as a moderate heavy fermion system. A phase transition was observed near 255 K, indicating complex physical properties.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Intermetallic compounds containing cerium (Ce) are crucial for understanding heavy fermion physics.
- Investigating the interplay between electronic structure, magnetism, and transport properties in Ce-based systems is key to discovering novel quantum phenomena.
Purpose of the Study:
- To comprehensively investigate the physical properties of the intermetallic compound CeRh2Ga2.
- To determine its crystal structure, magnetic behavior, and electronic ground state.
- To explore potential phase transitions and their impact on thermal and electrical transport.
Main Methods:
- Magnetic susceptibility measurements (magnetic susceptibility).
- Isothermal magnetization (M(H)) studies.
- Heat capacity (heat capacity) measurements.
- Electrical resistivity (electrical resistivity) measurements.
- Thermal conductivity (thermal conductivity) measurements.
- Thermopower (S(T)) measurements.
Main Results:
- CeRh2Ga2 crystallizes in a primitive tetragonal structure (CaBe2Ge2-type, space group P4/nmm) without long-range magnetic order down to 1.8 K.
- Magnetic susceptibility data indicate a Ce3+ valence state and paramagnetic behavior.
- Electrical resistivity and heat capacity data reveal Kondo lattice behavior and a metallic ground state, with an enhanced Sommerfeld coefficient (gamma = 150 mJ/mol K2) classifying it as a moderate heavy fermion system.
- An anomaly near 255 K in heat capacity and electrical resistivity suggests a phase transition.
- Thermal conductivity is dominated by phonons, and the Lorenz number (L(T)) significantly exceeds the theoretical Sommerfeld value (L0).
Conclusions:
- CeRh2Ga2 is identified as a moderate heavy fermion system exhibiting Kondo lattice behavior.
- A high-temperature phase transition occurs around 255 K, influencing the material's physical properties.
- Phonon-dominated thermal transport and a large Lorenz number suggest complex electronic interactions and potential deviations from standard Fermi liquid theory.
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