Title: The Triplet Resonating Valence Bond State and Superconductivity in Hund's Metals: II Mean-field theory*

Triplet resonating valence bond (tRVB) states are entangled states that are produced in anisotropic magnetic environments [1], just like how singlet RVB states arise in frustated antiferromagnetic systems. A single Iron atom in a cubic environment contains miniature triplet states resonating between various t2g orbitals of the d-shell due to the large Hund's coupling. I will discuss how this can be used to derive a local inter-orbital triplet pairing applicable to Iron-based superconductors [2]. While the order parameter contains significant inter-band pairing, the projection on the Fermi surface appears as an odd-parity intra-band triplet pairing which enjoys a weak-coupling instability and gaps out the entire Fermi surface. In analogy with the RVB theory, a Gutzwiller projected variational mean-field is suggested for the ground state. Furthermore, we augment our mean-field theory using a Kotliar-Liu slave-boson approach to include the effect of intra- and inter-orbital interactions. Experimental signatures of the proposed triplet superconductor are discussed in the next talk.

[1] B. Shen, et al, arXiv:1907.10470.
[2] P. Coleman, Y. Komijani, E. Koenig, arXiv:1910.03168.