# Temperature and doping induced instabilities of the repulsive Hubbard model on the Lieb lattice

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**Temperature and doping induced instabilities of the repulsive Hubbard model on the Lieb lattice.** / Kumar, Pramod; Vanhala, Tuomas I.; Törmä, Päivi.

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*Physical Review B*, Vuosikerta. 96, Nro 24, 245127, Sivut 1-11. https://doi.org/10.1103/PhysRevB.96.245127

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*Physical Review B*,

*96*(24), 1-11. [245127]. https://doi.org/10.1103/PhysRevB.96.245127

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TY - JOUR

T1 - Temperature and doping induced instabilities of the repulsive Hubbard model on the Lieb lattice

AU - Kumar, Pramod

AU - Vanhala, Tuomas I.

AU - Törmä, Päivi

PY - 2017/12/21

Y1 - 2017/12/21

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85039443603&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.96.245127

DO - 10.1103/PhysRevB.96.245127

M3 - Article

VL - 96

SP - 1

EP - 11

JO - Physical Review B (Condensed Matter and Materials Physics)

JF - Physical Review B (Condensed Matter and Materials Physics)

SN - 2469-9950

IS - 24

M1 - 245127

ER -

ID: 16955957