Chain of equations for two-time temperature-dependent Green's functions

1970 ◽  
Vol 4 (1) ◽  
pp. 678-685 ◽  
Author(s):  
V. D. Ozrin
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Temperature Dependent

PERMITTIVITY IN PERTURBED MOLECULAR NANOFILMS

2012 ◽  
Vol 26 (15) ◽  
pp. 1250078 ◽  
Author(s):  
BRANKO MARKOSKI ◽  
JOVAN P. ŠETRAJČIĆ ◽  
MIROSLAVA PETREVSKA ◽  
SINIŠA VUČENOVIĆ
Keyword(s):  
Optical Properties ◽  
Dielectric Properties ◽  
Green's Functions ◽  
Green’S Functions ◽  
Microscopic Theory ◽  
2D Systems ◽  
Molecular Films ◽  
Temperature Dependent

A microscopic theory of dielectric properties of thin molecular films, i.e., quasi 2D systems bounded by two surfaces parallel to XY planes was formulated. Harmonic exciton states were calculated using the method of two-time, retarded, temperature dependent Green's functions. It has been shown that two types of excitations can occur: bulk and surface exciton states. Analysis of the optical properties of these crystalline systems for low exciton concentration shows that the permittivity strongly depends on boundary parameters and the thickness of the film. Conditions for the appearance of localized or unoccupied exciton states have been especially analyzed.

The Tight-Binding Study of the Temperature Dependent Anti-Ferromagnetic Order in Graphene

2018 ◽  
Vol 24 (8) ◽  
pp. 5970-5974
Author(s):  
H. S Gouda ◽  
Sivabrata Sahu ◽  
G. C Rout
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Tight Binding ◽  
Nearest Neighbors ◽  
Hole Doping ◽  
Tight Binding Model ◽  
Temperature Dependent ◽  
Electron Hole ◽  
Binding Model ◽  
Model Study

We propose a tight binding model study for graphene taking the electron hopping up to third-nearest-neighbors. The graphene placed on different polarized substrates introduces in-equivalences in the two sub-lattices of honeycomb unit cell of graphene. Further the electron/hole doping in graphene enhances the in-equivalence in both the sub-lattices. The Hubbard type Coulomb interaction between the electrons in both sub-lattices generates anti-ferromagnetic (AFM) order in graphene under certain conditions. Zubarev’s Green’s functions method is applied to solve the Hamiltonian. The spins of the electron in the two sub-lattices are assumed to be oriented in opposite directions giving rise to AFM order in the system. The magnetization is calculated from the Green’s functions and computed self-consistently. The effect of the presence of substrates and doping concentrations on magnetization is reported here.

Permittivity in Molecular Nanofilms

2007 ◽  
Vol 1017 ◽  
Author(s):  
Sinisa Vucenovic ◽  
Dusan Ilic ◽  
Jovan Setrajcic ◽  
Vjekoslav Sajfert ◽  
Dragoljub Mirjanic
Keyword(s):  
Optical Properties ◽  
Green's Functions ◽  
Green’S Functions ◽  
Microscopic Theory ◽  
2D Systems ◽  
Molecular Films ◽  
Temperature Dependent ◽  
Dielectrical Properties

AbstractA microscopic theory of dielectrical properties of thin molecular films, i.e. quasi 2D systems bounded by two surfaces parallel to XY planes was formulated. Harmonic exciton states were calculated using the method of two-time, retarded, temperature dependent Green's functions. It has been shown that two types of excitations can occur: bulk and surface exciton states. Analysis of the optical properties of these crystalline systems for low exciton concentration shows that the permittivity strongly depends on boundary parameters and the thickness of the film. Conditions for the appearance of localized exciton states have been especially analyzed.

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