Halperin $(m',m,n)$ fractional quantum Hall effect in topological flat bands

Abstract

The Halperin $(m',m,n)$ fractional quantum Hall effects of two-component quantum particles are studied in topological checkerboard lattice models. Here for $m\neq m'$, we demonstrate the emergence of fractional quantum hall effects with the associated $\mathbf{K}=\begin{pmatrix} m+2 & 1\\ 1 & m\\ \end{pmatrix}$ matrix (even $m=2$ for boson and odd $m=3$ for fermion) in the presence of both strong intercomponent and intracomponent repulsions. Through exact diagonalization and density-matrix renormalization group calculations, we elucidate their topological fractionalizations, including (i) the $\det|\mathbf{K}|=(m^2+2m-1)$-fold ground-state degeneracies and (ii) fractionally quantized topological Chern number matrix $\mathbf{C}=\mathbf{K}^{-1}$. Our flat band model provides a paradigmatic example of a microscopic Hamiltonian featuring fractional quantum Hall effect with partial spin-polarization.