Order in Quantum Compass and Orbital eg Models
P. Czarnika,b, J. Dziarmagaa and A.M. Oleśa,c
aM. Smoluchowski Institute of Physics, Jagiellonian University, prof. S. Łojasiewicza 11, PL-30348 Kraków, Poland
bInstitute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
cMax Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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We investigate thermodynamic phase transitions in the compass model and in eg 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 𝓣c/J=0.0606(4). For the eg orbital model one finds: (i) a very accurate estimate of 𝓣c/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 𝓣c, while entanglement influences the quality of 𝓣c estimation.

DOI: 10.12693/APhysPolA.133.359
PACS numbers: 75.10.Jm, 05.10.Cc, 05.70.Fh, 75.25.Dk