Zobrazeno 1 - 10
of 309
pro vyhledávání: '"Derzhko, O."'
Publikováno v:
Phys. Rev. B 105 (2022) 064420
It is evidenced that effective lattice-gas models of hard-core monomers and dimers afford a proper description of low-temperature features of spin-1/2 Heisenberg diamond and octahedral chains. Besides monomeric particles assigned within the localized
Externí odkaz:
http://arxiv.org/abs/2110.07958
Publikováno v:
Condens. Matter Phys., 2018, vol. 21, No. 3, 33705
We consider the pyrochlore-lattice quantum Heisenberg ferromagnet and discuss the properties of this spin model at arbitrary temperatures. To this end, we use the Green's function technique within the random-phase (or Tyablikov) approximation as well
Externí odkaz:
http://arxiv.org/abs/1809.09951
Publikováno v:
Phys. Rev. Lett. 109, 096404 (2012)
We investigate the location and nature of the para-ferro transition of interacting electrons in dispersionless bands using the example of the Hubbard model on the Tasaki lattice. This case can be analyzed as a geometric site-percolation problem where
Externí odkaz:
http://arxiv.org/abs/1204.2110
Publikováno v:
Acta Phys. Pol. A 118 (2010) 742
Ground-state energy is exactly calculated for the spin-1/2 Heisenberg-Ising bond alternating chain with the Dzyaloshinskii-Moriya interaction. Under certain condition, which relates a strength of the Ising, Heisenberg and Dzyaloshinskii-Moriya intera
Externí odkaz:
http://arxiv.org/abs/1102.0847
Publikováno v:
Acta Physica Polonica A118 (2010) 736-737
We consider the one-orbital $N$-site repulsive Hubbard model on two kagome-like chains, both of which yield a completely dispersionless (flat) one-electron band. Using exact many-electron ground states in the subspaces with $n\le n_{\max}$ ($n_{\max}
Externí odkaz:
http://arxiv.org/abs/1009.3827
Publikováno v:
Phys. Rev. B 81, 014421 (2010)
We consider the repulsive Hubbard model on three highly frustrated one-dimensional lattices -- sawtooth chain and two kagom\'{e} chains -- with completely dispersionless (flat) lowest single-electron bands. We construct the complete manifold of {\em
Externí odkaz:
http://arxiv.org/abs/0911.3596
Publikováno v:
Physica B404 (2009) 3316-3319
Highly frustrated lattices yield a completely flat lowest single-electron band. Remarkably, exact many-body ground states can be constructed for the repulsive Hubbard model and the t-J model by filling this flat band with localized electron states. T
Externí odkaz:
http://arxiv.org/abs/0903.3296
Publikováno v:
J. Phys.: Conf. Ser. 145 (2009) 012059
We consider the antiferromagnetic Heisenberg model and the repulsive Hubbard model for a class of frustrated lattices with a completely dispersionless (flat) lowest one-particle (either one-magnon or one-electron) band. We construct exact many-partic
Externí odkaz:
http://arxiv.org/abs/0902.1627
Publikováno v:
Phys. Rev. B 78, 214415 (2008)
Using the coupled cluster method for high orders of approximation and complementary exact diagonalization studies we investigate the ground state properties of the spin-1/2 $J_1$--$J_2$ frustrated Heisenberg antiferromagnet on the square lattice. We
Externí odkaz:
http://arxiv.org/abs/0806.3825
Publikováno v:
Int. J. Modern Phys. B 22, 4418 (2008)
We report on recent studies of the spin-half Heisenberg and the Hubbard model on the sawtooth chain. For both models we construct a class of exact eigenstates which are localized due to the frustrating geometry of the lattice for a certain relation o
Externí odkaz:
http://arxiv.org/abs/0806.0922