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arXiv · 1502.02729

Strongly correlated flat-band systems: The route from Heisenberg spins to Hubbard electrons

Oleg Derzhko·Johannes Richter·Mykola Maksymenko
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Abstract

In this review we recapitulate the basic features of the flat-band spin systems and briefly summarize earlier studies in the field. Main emphasis is made on recent developments which include results for both spin and electron flat-band models. In particular, for flat-band spin systems we highlight field-driven phase transitions for frustrated quantum Heisenberg antiferromagnets at low temperatures, chiral flat-band states, as well as the effect of a slight dispersion of a previously strictly flat band due to nonideal lattice geometry. For electronic systems, we discuss the universal low-temperature behavior of several flat-band Hubbard models, the emergence of ground-state ferromagnetism in the square-lattice Tasaki-Hubbard model and the related Pauli-correlated percolation problem, as well as the dispersion-driven ground-state ferromagnetism in flat-band Hubbard systems. Closely related studies and possible experimental realizations of the flat-band physics are also described briefly.

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Oleg Derzhko, Johannes Richter, Mykola Maksymenko. 2015-04-13. Strongly correlated flat-band systems: The route from Heisenberg spins to Hubbard electrons. https://doi.org/10.1142/s0217979215300078

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