scholarly journals Doping effects on electronic states in electron-doped FeSe: Impact of self-energy and vertex corrections

2020 ◽  
Vol 102 (8) ◽  
Author(s):  
Youichi Yamakawa ◽  
Seiichiro Onari ◽  
Hiroshi Kontani
Keyword(s):  
Electronic States ◽  
Self Energy ◽  
Vertex Corrections ◽  
Doping Effects

scholarly journals Vertex Corrections in Gauge Theories for Two-dimensional Condensed Matter Systems

1998 ◽  
Vol 12 (16n17) ◽  
pp. 1673-1692 ◽  
Author(s):  
Peter Kopietz
Keyword(s):  
Gauge Field ◽  
Condensed Matter ◽  
Finite Energy ◽  
Energy Scale ◽  
Gauge Fields ◽  
Logarithmic Correction ◽  
Two Dimensional ◽  
Numerical Constant ◽  
Self Energy ◽  
Vertex Corrections

We calculate the self-energy of two-dimensional fermions that are coupled to transverse gauge fields, taking two-loop corrections into account. Given a bare gauge field propagator that diverges for small momentum transfers q as 1/qη, 1<η≤ 2, the fermionic self-energy without vertex corrections vanishes for small frequencies ω as Σ(ω)∝ ωγ with γ=2/(1+η)<1. We show that inclusion of the leading radiative correction to the fermion-gauge field vertex leads to Σ(ω)∝ωγ [1-aη ln (ω0/ω)], where aη is a positive numerical constant and ω0 is some finite energy scale. The negative logarithmic correction is consistent with the scenario that higher order vertex corrections push the exponent γ to larger values.

Mobility of spin polarons with vertex corrections

2019 ◽  
Vol 33 (18) ◽  
pp. 1950195
Author(s):  
Marcielow J. Callelero ◽  
Danilo M. Yanga
Keyword(s):  
Order Term ◽  
Hard Core ◽  
Hole Mobility ◽  
Boltzmann Distribution ◽  
Temperature Limit ◽  
Self Energy ◽  
Vertex Corrections ◽  
Bosonic Operator ◽  
Dirac Distribution ◽  
Ising Limit

The mobility of holes in the spin polaron theory is discussed in this paper using a representation where holes are described as spinless fermions and spins as normal bosons. The hard-core bosonic operator is introduced through the Holstein–Primakoff transformation. Mathematically, the theory is implemented in the finite temperature (Matsubara) Green’s function method. The expressions for the zeroth-order term of the hole mobility is determined explicitly for hole occupation factor taking the form of Fermi–Dirac distribution and the classical Maxwell–Boltzmann distribution function. These are proportional to the relaxation time and the square of the renormalization factor. In the Ising limit, we showed that the mobility is zero and the holes are localized. The calculation of the hole mobility is generalized by considering the vertex corrections, which included the ladder diagrams. One of the vertex functions in the hole mobility can be evaluated using the Ward identity for hole-spin wave weak interaction. We also derived an expression for the hole mobility with vertex corrections in the low-temperature limit and vanishing self-energy effects. Our calculation is made up to second-order correction in the case where the hole occupation factor follows the Fermi–Dirac distribution.

scholarly journals DUFFIN–KEMMER–PETIAU THEORY IN THE CAUSAL APPROACH

2002 ◽  
Vol 17 (02) ◽  
pp. 205-227 ◽  
Author(s):  
J. T. LUNARDI ◽  
B. M. PIMENTEL ◽  
J. S. VALVERDE ◽  
L. A. MANZONI
Keyword(s):  
Compton Scattering ◽  
Gauge Invariance ◽  
Vacuum Polarization ◽  
Effective Theory ◽  
Self Energy ◽  
Vertex Corrections ◽  
Causal Approach ◽  
Scalar Sector ◽  
Natural Way

In this paper we consider the scalar sector of Duffin–Kemmer–Petiau theory in the framework of Epstein–Glaser causal method. We calculate the lowest order distributions for Compton scattering, vacuum polarization, self-energy and vertex corrections. By requiring gauge invariance of the theory we recover, in a natural way, the scalar propagator of the usual effective theory.

EFFECTIVE MASS, LANDAU INTERACTION FUNCTION AND SELF-ENERGY OF AN ELECTRON LIQUID

1992 ◽  
Vol 06 (19) ◽  
pp. 3089-3145 ◽  
Author(s):  
HIROSHI YASUHARA ◽  
YUMI OUSAKA
Keyword(s):  
Effective Mass ◽  
Pauli Principle ◽  
Particle Dispersion ◽  
Mass Ratio ◽  
Correct Evaluation ◽  
Quasi Particle ◽  
Interaction Function ◽  
Self Energy ◽  
Vertex Corrections ◽  
Monotonically Decreasing Function

A review is given of the calculations of the effective mass m* for an electron liquid at metallic densities. The review will be helpful to understand that a great deal of difficulties are involved in estimating the quasi-particle dispersion in the vicinity of the Fermi level. It is emphasized that a systematic consideration of vertex corrections in accordance with the Pauli principle up to higher orders in calculating the Landau interaction function fσσ'( p , p ') or the self-energy Σ( p , ε) is indispensable for the correct evaluation of m* for rs>1. It is concluded that the mass ratio m*/m is a monotonically decreasing function of rs and remains smaller than unity throughout the whole region of metallic densities. The deviation of m*/m from unity is as small as 8% even at the lowest metallic densities. From general considerations we shall also discuss the effects of Σ( p , ε) on the overall features of the quasi-particle dispersion.

scholarly journals Superconductivity in In-doped AgSnBiTe3 with possible band inversion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsubasa Mitobe ◽  
Kazuhisa Hoshi ◽  
Md. Riad Kasem ◽  
Ryosuke Kiyama ◽  
Hidetomo Usui ◽  
...  
Keyword(s):  
Specific Heat ◽  
Single Phase ◽  
Electronic States ◽  
Pressure Effects ◽  
Partial Substitution ◽  
In Doping ◽  
Doping Effects ◽  
Wide Range ◽  
Band Inversion ◽  
Structural And Electronic Properties

AbstractWe investigated the chemical pressure effects on structural and electronic properties of SnTe-based material using partial substitution of Sn by Ag0.5Bi0.5, which results in lattice shrinkage. For Sn1−2x(AgBi)xTe, single-phase polycrystalline samples were obtained with a wide range of x. On the basis of band calculations, we confirmed that the Sn1−2x(AgBi)xTe system is basically possessing band inversion and topologically preserved electronic states. To explore new superconducting phases related to the topological electronic states, we investigated the In-doping effects on structural and superconducting properties for x = 0.33 (AgSnBiTe3). For (AgSnBi)(1−y)/3InyTe, single-phase polycrystalline samples were obtained for y = 0–0.5 by high-pressure synthesis. Superconductivity was observed for y = 0.2–0.5. For y = 0.4, the transition temperature estimated from zero-resistivity state was 2.4 K, and the specific heat investigation confirmed the emergence of bulk superconductivity. Because the presence of band inversion was theoretically predicted, and the parameters obtained from specific heat analyses were comparable to In-doped SnTe, we expect that the (AgSnBi)(1−y)/3InyTe and other (Ag, In, Sn, Bi)Te phases are candidate systems for studying topological superconductivity.

The self-energy beyond GW: Local and nonlocal vertex corrections

2009 ◽  
Vol 131 (15) ◽  
pp. 154111 ◽  
Author(s):  
P. Romaniello ◽  
S. Guyot ◽  
L. Reining
Keyword(s):  
The Self ◽  
Self Energy ◽  
Vertex Corrections
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