Odd-parity triplet pair induced by Hund's rule coupling

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Materials Science

Background:

• Orbital degeneracy in condensed matter systems leads to complex electronic behaviors.
• Understanding pair states is crucial for developing novel quantum materials.

Purpose of the Study:

• To elucidate the microscopic formation mechanism of odd-parity triplet pairs.
• To define pair states using the concept of off-diagonal long-range order.

Main Methods:

• Utilized numerical techniques to analyze pair correlation functions.
• Applied the concept of off-diagonal long-range order to define pair states.
• Investigated systems with orbital degeneracy and two sites per unit cell.

Main Results:

• Defined an odd-parity triplet pair as the eigenstate with the maximum eigenvalue of a pair correlation function.
• Identified the odd-parity triplet pair as an out-of-phase combination of local triplets.
• Demonstrated the crucial role of Hund's rule coupling in inducing these pairs.

Conclusions:

• The study provides a clear microscopic picture of odd-parity triplet pair formation.
• Hund's rule coupling is essential for generating these specific pair states in the studied lattice systems.
• The findings contribute to the understanding of exotic electronic states in degenerate systems.