Correlation between ground state and orbital anisotropy in heavy fermion materials

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Emergent phenomena arise from complex interactions between structural, orbital, charge, and spin degrees of freedom.
• Understanding these interdependencies is crucial for discovering novel quantum phases like superconductivity.
• Cerium-based heavy fermion compounds offer a unique platform to study these intricate relationships.

Purpose of the Study:

• To investigate the correlation between orbital anisotropy and ground-state properties in CeRh1-xIrxIn5.
• To accurately determine the 4f crystal-electric field ground-state wave functions in these strongly correlated materials.
• To elucidate the role of orbital anisotropy in driving distinct ground states, including antiferromagnetism and superconductivity.

Main Methods:

• Utilized linear polarization-dependent soft X-ray absorption spectroscopy (XAS) for high-accuracy measurements.
• Synthesized and studied a substitution series of CeRh1-xIrxIn5 to cover a range of ground states.
• Analyzed the measured 4f crystal-electric field ground-state wave functions.

Main Results:

• Accurately determined the 4f crystal-electric field ground-state wave functions for CeRh1-xIrxIn5.
• Demonstrated a clear correlation between these wave functions and the observed ground-state properties.
• Observed distinct ground states including long-range antiferromagnetic order, unconventional superconductivity, and their coexistence.

Conclusions:

• Orbital anisotropy is a key factor influencing the ground states in cerium-based heavy fermion compounds.
• The interplay of electronic degrees of freedom, particularly orbital character, dictates the emergence of complex phenomena.
• This study provides critical insights into the fundamental mechanisms underlying superconductivity and magnetism in correlated electron systems.