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arXiv · 0904.4755

Magnetic phase diagram of the Hubbard model with next-nearest-neighbour hopping

Robert Peters·Thomas Pruschke
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Abstract

We calculate the magnetic phase diagram of the Hubbard model for a Bethe lattice with nearest neighbour (NN) hopping $t_1$ and next nearest neighbour (NNN) hopping $t_2$ in the limit of infinite coordination. We use the amplitude $t_2/t_1$ of the NNN hopping to tune the density of states (DOS) of the non-interacting system from a situation with particle-hole symmetry to an asymmetric one with van-Hove singularities at the lower ($t_2/t_1>0$) respectively upper ($t_2/t_1<0$) band edge for large enough $|t_2/t_1|$. For this strongly asymmetric situation we find rather extended parameter regions with ferromagnetic states and regions with antiferromagnetic states.

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Robert Peters, Thomas Pruschke. 2009-04-30. Magnetic phase diagram of the Hubbard model with next-nearest-neighbour hopping. https://doi.org/10.1088/1367-2630%2F11%2F8%2F083022

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