Fractional charge and emergent mass hierarchy in diagonal two-leg t-J cylinders

TL;DR

This study introduces diagonal t-J ladders rotated relative to the square lattice, revealing charge density waves, spin-charge separation, and solitons with fractionalized quantum numbers and vastly different effective masses.

Contribution

It defines a new class of diagonal t-J ladders and uncovers novel fractionalized excitations with emergent mass hierarchy using DMRG.

Findings

At x=1/4, the system forms a period 4 charge density wave.

Slight doping away from 1/4 reveals topologically distinct solitons.

Emergent solitons have effective masses differing by several orders of magnitude.

Abstract

We define a new class of "diagonal" t-J ladders rotated by $\pi$/4 relative to the canonical lattice directions of the square lattice, and study it using density matrix renormalization group (DMRG). Here, we focus on the two-leg cylinder with a doped hole concentration near x = 1/4. At exactly x = 1/4, the system forms a period 4 charge density wave (CDW) and exhibits spin-charge separation. Slightly away from 1/4 doping we observe several topologically distinct types of solitons with well defined fractionalized quantum numbers. Remarkably, given the absence of any obvious small parameter, the effective masses of the emergent solitons differ by several orders of magnitude.