Phase diagram of interacting fermionic two-leg ladder with pair hopping**Project supported by the Open Project of the State Key Laboratory of Surface Physics in Fudan University, China (Grant No. KF2018_13) and the Ph. D. Research Startup Foundation of Anhui University (Grant No. J01003310).

Abstract

We study the phase diagram of the interacting fermionic two-leg ladder, which is featured by pair hopping and interactions of singlet and triplet superconducting channels. By using Abelian bosonization method, we obtain the full phase diagram of our model. The superconducting triplet pairing phase is characterized by a fractional edge spin and interpreted as two Kitaev chains under the mean filed approximation. The pair hopping will give rise to spin-density-wave (SDW) orders and can also support Majorana edge modes in spin channel. At half filling, the resulting Majorana-SDW phase shows additional fractionalization in charge channel, and can be interpreted as two Su–Schrieffer–Heeger (SSH) chains in the mean field regime.