Abstract
The critical behaviour of a two-orbital model with degenerate d xz and dyz orbitals is investigated by multi-dimensional bosonization. We find that the corresponding bosonic theory has an overdamped collective mode with dynamical exponent z = 3, which appears to be a general feature of a two-orbital model and becomes the dominant fluctuation in the vicinity of the orbital-ordering quantum critical point. Since the very existence of this z = 3 overdamped collective mode induces non-Fermi liquid behaviour near the quantum critical point, we conclude that a two-orbital model generally has a sizable area in the phase diagram showing non-Fermi liquid behaviour. Furthermore, we show that the bosonic theory resembles the continuous model near the d-wave Pomeranchuk instability, suggesting that orbital order in a two-orbital model is identical to nematic order in a continuous model. Our results can be applied to systems with degenerate dxz and d yz orbitals such as iron-based superconductors and bilayer strontium ruthenates Sr3Ru2O7.
Original language | English (US) |
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Article number | 50007 |
Journal | EPL |
Volume | 101 |
Issue number | 5 |
DOIs | |
State | Published - Mar 2013 |
ASJC Scopus subject areas
- General Physics and Astronomy