@article{2dafce6a570c4e0ba9b5cac8654bd668, title = "Temperature and doping induced instabilities of the repulsive Hubbard model on the Lieb lattice", abstract = "The properties of a phase at finite interactions can be significantly influenced by the underlying dispersion of the noninteracting Hamiltonian. We demonstrate this by studying the repulsive Hubbard model on the two-dimensional Lieb lattice, which has a flat band for vanishing interaction U. We perform real-space dynamical mean-field theory calculations at different temperatures and dopings using a continuous-time quantum Monte Carlo impurity solver. Studying the frequency dependence of the self-energy, we find that a nonmagnetic metallic region at finite temperature displays non-Fermi-liquid behavior, which is a concomitant of the flat-band singularity. At half-filling, we also find a magnetically ordered region, where the order parameter varies linearly with the interaction strength, and a strongly correlated Mott insulating phase. The double occupancy decreases sharply for small U, highlighting the flat-band contribution. Away from half-filling, we observe the stripe order, i.e., an inhomogeneous spin and charge density wave of finite wavelength, which turns into a sublattice ordering at higher temperatures.", author = "Pramod Kumar and Vanhala, {Tuomas I.} and P{\"a}ivi T{\"o}rm{\"a}", year = "2017", month = "12", day = "21", doi = "10.1103/PhysRevB.96.245127", language = "English", volume = "96", pages = "1--11", journal = "Physical Review B (Condensed Matter and Materials Physics)", issn = "2469-9950", publisher = "American Physical Society", number = "24", }