scholarly journals Possible half-metallic phase in bilayer graphene: Calculations based on mean-field theory applied to a two-layer Hubbard model

2013 ◽  
Vol 88 (20) ◽  
Author(s):  
Jie Yuan ◽  
Dong-Hui Xu ◽  
Hao Wang ◽  
Yi Zhou ◽  
Jin-Hua Gao ◽  
...  
Keyword(s):  
Field Theory ◽  
Hubbard Model ◽  
Mean Field Theory ◽  
Mean Field ◽  
Bilayer Graphene ◽  
Metallic Phase ◽  
Half Metallic

COMPREHENSIVE MEAN FIELD THEORY FOR THE HUBBARD MODEL

1992 ◽  
Vol 06 (05n06) ◽  
pp. 731-747 ◽  
Author(s):  
V. JANIŠ ◽  
D. VOLLHARDT
Keyword(s):  
Field Theory ◽  
Energy Transfer ◽  
Hubbard Model ◽  
Entire Range ◽  
Mean Field Theory ◽  
Mean Field ◽  
Exact Expression ◽  
Grand Potential ◽  
Input Parameters

We derive an exact expression for the grand potential of the Hubbard model in d=∞ dimensions. By simplifying the energy transfer between up and down spins we obtain a comprehensive mean-field theory for this model. It is (i) thermodynamically consistent in the entire range of input parameters, (ii) conserving and, (iii) exact in several non-trivial limits, e. g. in the free (U→0), atomic (t→0) and Heisenberg (U≫t, n=1) limit.

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