Temat: 75.25.Dk - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Quantum Phase Transitions in the Kitaev-Heisenberg Model on a Single Hexagon
Autorzy:: Gotfryd, D.
Oleś, A.
Powiązania:: https://bibliotekanauki.pl/articles/1385471.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Jm
75.25.Dk
75.30.Et
Opis:: We present a detailed analysis of the Kitaev-Heisenberg model on a single hexagon. The energy spectra and spin-spin correlations obtained using exact diagonalisation indicate quantum phase transitions between antiferromagnetic and anisotropic spin correlations when the Kitaev interactions increase. In cluster mean-field approach frustrated nearest neighbor exchange stabilizes the stripe phase in between the Néel phase and frustrated one which evolves towards the Kitaev spin liquid.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 318-320
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Exotic Spin Order due to Orbital Fluctuations
Autorzy:: Brzezicki, W.
Dziarmaga, J.
Oleś, A.
Powiązania:: https://bibliotekanauki.pl/articles/1374350.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Jm
03.65.Ud
64.70.Tg
75.25.Dk
Opis:: We investigate the phase diagrams of the spin-orbital $d^9$ Kugel-Khomskii model for increasing system dimensionality: from the square lattice monolayer, via the bilayer to the cubic lattice. In each case we find strong competition between different types of spin and orbital order, with entangled spin-orbital phases at the crossover from antiferromagnetic to ferromagnetic correlations in the intermediate regime of Hund's exchange. These phases have various types of exotic spin order and are stabilized by effective interactions of longer range which follow from enhanced spin-orbital fluctuations. We find that orbital order is in general more robust while spin order melts first under increasing temperature, as observed in several experiments for spin-orbital systems.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-40-A-49
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Order in Quantum Compass and Orbital e_{g} Models
Autorzy:: Czarnik, P.
Dziarmaga, J.
Oleś, A.
Powiązania:: https://bibliotekanauki.pl/articles/1029762.pdf
Data publikacji:: 2018-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Jm
05.10.Cc
05.70.Fh
75.25.Dk
Opis:: We investigate thermodynamic phase transitions in the compass model and in e_{g} orbital model on an infinite square lattice by variational tensor network renormalization (VTNR) in imaginary time. The onset of nematic order in the quantum compass model is estimated at _{c}/J=0.0606(4). For the e_{g} orbital model one finds: (i) a very accurate estimate of _{c}/J=0.3566± 0.0001 and (ii) the critical exponents in the Ising universality class. Remarkably large difference in frustration results in so distinct values of _{c}, while entanglement influences the quality of _{c} estimation.
Źródło:: Acta Physica Polonica A; 2018, 133, 3; 359-361
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Entangled Spin-Orbital Phases in the $d^{9}$ Model
Autorzy:: Brzezicki, W.
Oleś, A.
Powiązania:: https://bibliotekanauki.pl/articles/1426843.pdf
Data publikacji:: 2012-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Jm
03.65.Ud
64.70.Tg
75.25.Dk
Opis:: We investigate the phase diagrams of the spin-orbital $d^9$ Kugel-Khomskii model for a bilayer and a monolayer square lattice using the Bethe-Peierls-Weiss method. For a bilayer we obtain valence bond phases with interlayer singlets, with alternating planar singlets, and two entangled spin-orbital phases, in addition to the antiferromagnetic and ferromagnetic order. Possibility of such entangled phases in a monolayer is under investigation at present.
Źródło:: Acta Physica Polonica A; 2012, 121, 5-6; 1045-1047
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Frustration and Entanglement in Compass and Spin-Orbital Models
Autorzy:: Oleś, Andrzej
Powiązania:: https://bibliotekanauki.pl/articles/1384027.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Jm
64.70.Tg
75.25.Dk
79.60.-i
Opis:: We review the consequences of intrinsic frustration of the orbital superexchange and of spin-orbital entanglement. While the Heisenberg perturbing interactions remove frustration in the compass model, the lowest columnar excitations are robust in the nanoscopic compass clusters and might be used for quantum computations. Entangled spin-orbital states determine the ground states in some cases, while in others concern excited states and lead to measurable consequences, as in the RVO₃ perovskites. On-site entanglement for strong spin-orbit coupling generates the frustrated Kitaev-Heisenberg model with a rich magnetic phase diagram on the honeycomb lattice. Frustration is here reflected in hole propagation which changes from coherent in an antiferromagnet via hidden quasiparticles in zigzag and stripe phases to entirely incoherent one in the Kitaev spin liquid.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 163-169
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 6.

Tytuł:: Hole Propagation in the Orbital Compass Models
Autorzy:: Brzezicki, W.
Daghofer, M.
Oleś, A.
Powiązania:: https://bibliotekanauki.pl/articles/1385190.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 75.10.Jm
03.65.Ud
64.70.Tg
75.25.Dk
Opis:: We explore the propagation of a single hole in the generalized quantum compass model which interpolates between fully isotropic antiferromagnetic phase in the Ising model and nematic order of decoupled antiferromagnetic chains for frustrated compass interactions. We observe coherent hole motion due to either interorbital hopping or due to the three-site effective hopping, while quantum spin fluctuations in the ordered background do not play any role.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 263-265
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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