Ferromagnetism in the Hubbard models with degenerate single-electron ground states

Tasaki, Hal

doi:10.1103/physrevlett.69.1608

Cited by 557 publications

(547 citation statements)

References 12 publications

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“…Bands that are nearly flat and/or feature a nontrivial topological invariant, similar to Landau levels producing the quantum Hall effects [2][3][4], have been considered in recent theoretical works [5][6][7][8][9][10][11][12] and can be realized in ultracold gas experiments [13][14][15]. Flat-band ferromagnetism has been studied first by Lieb [16] and, subsequently, by Tasaki and Mielke [17][18][19][20]. More recently it has been shown that the high density of states of flat bands enhances the superconducting critical temperature [21,22].…”

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confidence: 99%

Geometric Origin of Superfluidity in the Lieb-Lattice Flat Band

et al. 2016

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The ground state and transport properties of the Lieb lattice flat band in the presence of an attractive Hubbard interaction are considered. It is shown that the superfluid weight can be large even for an isolated and strictly flat band. Moreover the superfluid weight is proportional to the interaction strength and to the quantum metric, a band structure quantity derived solely from the flat-band Bloch functions. These predictions are amenable to verification with ultracold gases and may explain the anomalous behaviour of the superfluid weight of high-Tc superconductors.

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Geometric Origin of Superfluidity in the Lieb-Lattice Flat Band

et al. 2016

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“…The studies based on the Hubbard model have been continued since the 1930's. In recent two decades, remarkable progress has been made about flatband ferromagnetism [10][11][12] and itinerant ferromagnetism in the Hubbard model [13,14]. We also note that an attempt to realize flatband ferromagnetism on a decorated square lattice was indeed proposed for quantum dot systems [15].…”

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Magnetically Ordered State of Cold Fermions on a Decorated Square Lattice

et al. 2009

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We study two-component ultracold fermions with repulsive interactions, which are loaded into a decorated square lattice. By combining the real-space dynamical mean-field theory with the numerical renormalization group method, we discuss magnetic properties in the system. It is clarified how the ferromagnetically ordered ground state, which is stabilized by a flat band mechanism, is adiabatically connected to the ferrimagnetically ordered state expected in the strong coupling limit.

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“…In general, the triplet SC [1], which is connected with topological SC [2,3] and becomes hot topic recently, is believed to be driven by ferromagnetic spin fluctuations near the FM order. However, the realization of itinerant FM from the Stoner criterion [4] usually requires finite and, most of the time, strong electron interactions [5][6][7][8][9][10][11][12][13], which is hard to deal with in the weak coupling perturbative approaches. One way to overcome this difficulty is through the introducing of divergent density of states (DOS) at the Van Hove (VH) singularities of the system, which can induce these instabilities without strong electronic interactions.…”

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confidence: 99%

Itinerant ferromagnetism andp+ip′superconductivity in doped bilayer silicene

2015

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We study the electronic instabilities of doped bilayer silicene using the random phase approximation. In contrast to the singlet d + id superconductivity at the low doping region, we find that the system is an itinerant ferromagnet in the narrow doping regions around the Van Hove singularities, and a triplet p + ip superconductor in the vicinity of these regions. Adding a weak Kane-Mele spin-orbit coupling to the system further singles out the time-reversal invariant equal-spin helical p + ip pairing as the leading instability. The triplet pairing identified here is driven by the ferromagnetic fluctuations, which become strong and enhance the superconducting critical temperature remarkably near the phase boundaries between ferromagnetism and superconductivity.

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Ferromagnetism in the Hubbard models with degenerate single-electron ground states

Cited by 557 publications

References 12 publications

Geometric Origin of Superfluidity in the Lieb-Lattice Flat Band

Geometric Origin of Superfluidity in the Lieb-Lattice Flat Band

Magnetically Ordered State of Cold Fermions on a Decorated Square Lattice

Itinerant ferromagnetism andp+ip′superconductivity in doped bilayer silicene

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