Odd-Parity Triplet Pair Induced by Hund's Rule Coupling

TL;DR

This paper investigates how Hund's rule coupling induces odd-parity triplet pairing in orbital degenerate systems, providing a microscopic understanding through numerical analysis of pair correlation functions.

Contribution

It introduces a novel numerical scheme to define pair states via the eigenstate of the pair correlation function, revealing the microscopic origin of odd-parity triplet pairs.

Findings

Odd-parity triplet pairs arise as out-of-phase combinations of local triplets.

Hund's rule coupling induces local triplet states in the system.

The scheme clarifies the microscopic mechanism of triplet pairing in orbital degenerate systems.

Abstract

We discuss microscopic aspects of odd-parity triplet pair in orbital degenerate systems. From the concept of off-diagonal long-range order, a pair state is unambiguously defined as the eigenstate with the maximum eigenvalue of pair correlation function. Performing this scheme by a numerical technique, we clarify that the odd-parity triplet pair occurs as an out-of-phase combination of local triplets induced by Hund's rule coupling for the lattice including two sites in the unit cell.