Quasiparticle band structures

Fig. 44. Transitions across hybridization gaps of the quasiparticle band structure (a) can, depending on the position of the chemical potential (assumed inside the pseudogap for this calculation), and on the other band-structure features, give rise to pronounced structures in the non-local interaction part Y = x K of the Stoner denominator [compare eqs. (19) and (20)] at small wavevectors (b). In (b) a = y/ir with y defined in eq. (20) is varied somewhat around its proper value of (Grewe and Welslau 1988) to exhibit the strong tendency towards a magnetic instability occurring for Y(9 it> i/ = 0) = l.

T. Miyake, and S. Saito, Quasiparticle band structure of carbon nanotubes. Physical Review B, 2003. 68(15) p. 155424. 

Fig. 151. Quasiparticle band structure of UPt, and CeCujSij. Note the d bands at the left-hand side of the figure. (After Marabelli and Wachter 1987c.)...

The quasiparticle band structure under external parameters The external parameters we consider in this section arc the effects of a strong magnetic field and high pressure. Concerning an external magnetic field up to 35 T as measured on UPt3 by Franse et al. (1984), the authors observe a tendency to saturation above about 30 T at 4K, and by extrapolation that saturation is achieved at about 50 T with a... 

Fig. 119. The quasiparticle band structure for YH3 with (i) BiF3-type and (ii) LaF3-type structures. The filled circles (empty triangles) denote the valence (conduction) bands. The soUd lines represent the LDA band (Miyake...

Figure B3.2.1. The band structure of hexagonal GaN, calculated using EHT-TB parameters detemiined by a genetic algorithm [23]. The target energies are indicated by crosses. The target band structure has been calculated with an ab initio pseudopotential method using a quasiparticle approach to include many-particle corrections [194].

At this time, the fastest growing area in the field of nanophysics is in the studies of buckyballs and nanotubes. After the discovery [33] of the Qo molecule, many properties of the molecule and solids formed from the molecule were explored. The doped C6o crystals showed interesting behavior, including superconductivity. [34] The standard model, including the GW quasiparticle theory, was used [35] successfully to explore the energy band structure, and the superconducting properties appear to be consistent with the BCS theory. [36]... 

Fig. 21. Real part of the conductivity of YbFe4St>i2- The symbols on die left axis represent dc values at different temperatures. Below T (fv 50 K), a narrow peak at zero frequency and a gap-like feature at 18 meV gradually develop. Inset Renormalized band structure calculated from die Anderson lattice Hamiltonian. % and f denote bands of free carriers and localized electrons, respectively. At low temperatures a direct gap A opens. The Fermi level, Ep is near die top of die lower band,, resulting in hole-like character and enhanced effective mass of die quasiparticles (Dordevic et al., 2001).

The density functional theory (DFT) [7,8] is now widely used in studying both infinite bulk crystalline materials and finite atoms, molecules, and clusters. In principle, the ground-state total energy as well as the electron density itself in interacting many-electron systems is accurately described in DFT. Therefore, the geometry optimization by minimizing the total energy should also be accurate in DFT as well. The electronic band structure is, on the other hand, a very useful but approximate physical concept based on the quasiparticle theory for inter-... 

The elementary excitations of a conjugated polymer chain can be described within the mono-electronic approach as electron and hole quasiparticles [74] in a one-dimensional band structure, possibly weakly bound into extended Wannier-type excitons [71,75]. Within this framework, electron-phonon interactions lead to a peculiar family of exotic excitations including solitons, polarons, polaron pairs and bipolarons. In many cases, however, disorder is so significant that the polymer films are better described as an ensemble of relatively short conjugated segments [76], essentially behaving... 

More advanced techniques take into account quasiparticle corrections to the DFT-LDA eigenvalues. Quasiparticles are a way of conceptualizing the elementary excitations in electronic systems. They can be determined in band structure calculations that properly include the effects of exchange and correlation. In the... 

Louie S G 1987 Theory of quasiparticle energies and excitation spectra of semiconductors and insulators Electronic Band Structure and Its Applications (Lecture Notes in Physics vol 283) ed M Youssouf (Berlin Springer)... 

S. Suhai, Phys. Rev., B27, 3506 (1983). Quasiparticle Energy-Band Structures in Semicon-... 

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