arXiv 0803.06832008-03-05cond-mat.supr-con

Real space Bogolubov-de Gennes equations study of the boson-fermion model

Jaromir Krzyszczak, Tadeusz Domański, Karol I. Wysokiński

备注：: 5 pages with 5 Postscript figures, presented at 13 Krajowa Szkola Nadprzewodnictwa (Ladek-Zdroj 2007), will be published in APP-A, uses appolb.cls

英文摘要：

The boson-fermion (BF) model has been proposed to describe superconductivity in short coherence length superconductors. In this work we use it to study impurity induced inhomogeneities in high temperature superconductors (HTS) as found in numerous scanning tunnelling measurements. The model has been formulated in real space and solved with help of Bogolubov-de Gennes approach. Disorder in the boson or fermion subsystem is directly coupled to the superconducting order parameter and leads to severe changes of superconducting properties like local order parameter and density of states. We present the results for many impurities randomly distributed over otherwise clean and periodic two-dimensional square lattice.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

阅读原文

阅读 PDF ↗

arXiv 页面 ↗HTML 原文 ↗

本文内容

英文摘要相关论文

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

继续探索

相关论文

Vortex Core States in Superconducting Graphene

The distinctive features of the electronic structure of vortex states in superconducting graphene are studied within the Bogolubov-de Gennes theory applied to excitations near the Dirac point. We suggest a scenario describing the subgap spectrum transformation which occurs with a change in the doping level. For an arbitrary vorticity and doping level we investigate the problem of existence of zero energy modes. The crossover to a Caroli - de Gennes - Matricon type of spectrum is studied.

2009-01-22cond-mat.supr-con

Aharonov-Bohm Effect for Quasiparticles around a Vortex Line in a D-wave Superconductor

On the basis of the Bogolubov-de Gennes theory we develop an analytical description of low-energy extended quasiparticle states around an isolated flux line in a superconductor with gap nodes. The wavefunctions of these excitations and the corresponding density of states are shown to be strongly influenced by the interaction with a pure gauge potential due to the Aharonov-Bohm scenario.

2000-07-20cond-mat.supr-con

Electronic Structure of Vortices Pinned by Columnar Defects

The electronic structure of a vortex line trapped by an insulating columnar defect in a type-II superconductor is analysed within the Bogolubov-de Gennes theory. For quasiparticle trajectories with small impact parameters defined with respect to the vortex axis the normal reflection of electrons and holes at the defect surface results in the formation of an additional subgap spectral branch. The increase in the impact parameter at this branch is accompanied by the decrease of the excitation energy. When the impact parameter exceeds the radius of the defect this branch transforms into the Carol…

2009-01-06cond-mat.supr-con

Geometry -- dependent effects in Majorana nanowires

Starting from the Bogolubov - de Gennes theory describing the induced p-wave superconductivity in the Majorana wire of an arbitrary shape, we predict a number of intriguing phenomena such as the geometry-dependent phase battery (or a phi-Josephson junction with the spontaneous superconducting phase difference) and generation of additional quasiparticle modes at the Fermi level with the spatial position tuned by the external magnetic field direction. This tuning can be used to extend the capabilities of the braiding protocols in Majorana networks.

2020-01-17cond-mat.mes-hallcond-mat.supr-con

Topological symmetry classes for non-Hermitian models and connections to the bosonic Bogoliubov-de Gennes equation

The Bernard-LeClair (BL) symmetry classes generalize the ten-fold way classes in the absence of Hermiticity. Within the BL scheme, time-reversal and particle-hole come in two flavors, and "pseudo-Hermiticity" generalizes Hermiticity. We propose that these symmetries are relevant for the topological classification of non-Hermitian single-particle Hamiltonians and Hermitian bosonic Bogoliubov-de Gennes (BdG) models. We show that the spectrum of any Hermitian bosonic BdG Hamiltonian is found by solving for the eigenvalues of a non-Hermitian matrix which belongs to one of the BL classes. We theref…

2018-08-26cond-mat.mes-hallcond-mat.quant-gascond-mat.supr-con

Dynamically current-driven de Gennes -St James states in Metal-Superconductor junctions

We investigate the conductance of a Normal-Normal'-Superconductor (NN'S) junction, in which current injection destroys superconductivity in a small region N' of the superconductor, with a size varying with the applied voltage V. Voltage-dependent de Gennes-Saint James (dGSJ) bound states appearing in the N' slab lead to two distinct sets of conductance oscillations. We show that this effect significantly alters the conductance of systems for which $κ^2v_F \sim 10^9$ m/s such as pnictides ($κ$ and $v_F$ being the Ginzburg number and the Fermi velocity, respectively), and we discuss their conseq…

2016-04-28cond-mat.supr-con

更多相关论文收起更多论文

Higgs Boson in Superconductors

Superfluid helium, describable by a two-component order parameter, exhibits only the Bogolubov mode with energy $\to 0$ at long wavelengths, while a Lorentz-invariant theory with a two-component order parameter exhibits a finite energy mode at long wavelengths (the Higgs Boson), besides the above mass-less mode. The mass-less mode moves to high energies if it couples to electromagnetic fields (the Anderson-Higgs mechanism). Superconductors, on the other hand have been theoretically and experimentally shown to exhibit both modes. This occurs because the excitations in superconductors have an (a…

2001-09-21cond-mat.stat-mechcond-mat.supr-conhep-ph

Coexistence of superconductivity and incommensurate magnetic order

The influence of incommensurate spin density waves (SDW) on superconductivity in unconventional superconductors is studied by means of the Bogolubov-de Gennes (BdG) equations. Exploiting translational symmetries of a magnetically ordered two-dimensional system we propose an approach that allows to solve the BdG equations on much larger clusters than it is usually possible for inhomogeneous systems. Applying this approach we demonstrate that the presence of incommensurate spin density waves induces real-space inhomogeneity of the superconducting order parameter even in the absence of external m…

2011-09-16cond-mat.supr-con

Equation for the superfluid gap obtained by coarse graining the Bogoliubov-de Gennes equations throughout the BCS-BEC crossover

We derive a nonlinear differential equation for the gap parameter of a superfluid Fermi system by performing a suitable coarse graining of the Bogoliubov-de Gennes (BdG) equations throughout the BCS-BEC crossover, with the aim of replacing the time-consuming solution of the original BdG equations by the simpler solution of this novel equation. We perform a favorable numerical test on the validity of this new equation over most of the temperature-coupling phase diagram, by an explicit comparison with the full solution of the original BdG equations for an isolated vortex. We also show that the n…

2014-02-20cond-mat.quant-gascond-mat.supr-con

铁磁-超导异质结构中超导涡旋上磁振子的束缚态与散射

Bound states and scattering of magnons on a superconducting vortex in ferromagnet-superconductor heterostructures

该研究采用Bogolubov-de Gennes哈密顿量，探究含单个超导涡旋的铁磁-超导异质结构中磁振子的束缚态与散射特性，揭示了局域态数量的决定因素与斜散射等现象。

2024-09-16cond-mat.mes-hallcond-mat.supr-con

Real space inhomogeneities in high temperature superconductors: the perspective of two-component model

The two-component model of high temperature superconductors in its real space version has been solved using Bogoliubov-de Gennes equations. The disorder in the electron and boson subsystem has been taken into account. It strongly modifies the superconducting properties and leads to local variations of the gap parameter and density of states. The assumption that the impurities mainly modify boson energies offers natural explanation of the puzzling positive correlation between the positions of impurities and the values of the order parameter found in the scanning tunnelling microscopy experiment…

2010-07-21cond-mat.supr-con

Study on nonmagnetic impurities in the superconducting state of two-dimensional t-J model

We study the effect of nonmagnetic impurities in the superconducting state of the t-J model. The Bogoliubov de Gennes equation is derived using a slave-boson mean-field approximation, and we solve it numerically at T=0. The d_{x^2-y^2}-wave order parameter is suppressed near an impurity and its spatial variation induces the extended s-wave component. We also find the local charge density wave (CDW)-like feature due to the Friedel oscillations. This leads to the splitting of the expected zero-energy Andreev bound state. Therefore the system is unlikely introducing a localized state of other sym…

1998-04-07cond-mat.str-elcond-mat.supr-con

Ground State Description of a Single Vortex in an Atomic Fermi gas: From BCS to Bose-Einstein Condensation

We use a Bogoliubov-de Gennes (BdG) formulation to describe a single vortex in a neutral fermionic gas. It is presumed that the attractive pairing interaction can be arbitrarily tuned to exhibit a crossover from BCS to Bose-Einstein condensation. Our starting point is the BCS-Leggett mean field ground state for which a BdG approach is microscopically justified. At strong coupling, we demonstrate that this approach is analytically equivalent to the Gross-Pitaevskii description of vortices in true bosonic systems. We analyze the sizable density depletion found for the unitary regime and relate i…

2005-10-26cond-mat.quant-gascond-mat.str-elcond-mat.supr-con

Droplets of the order parameter in a low density attracting electron system in the presence of a strong random potential

The properties of a two-dimensional low density (n<<1) electron system with strong onsite Hubbard attraction U>W (W is the bandwidth) in the presence of a strong random potential V uniformly distributed in the range from -V to +V are considered. Electronic hoppings only at neighboring sites on the square lattice are taken into account, thus W=8t. The calculations were carried out for a lattice of 24x24 sites with periodic boundary conditions. In the framework of the Bogoliubov - de Gennes approach we observed an appearance of inhomogeneous states of spatially separated Fermi-Bose mixture of Co…

2020-06-23cond-mat.dis-nncond-mat.quant-gascond-mat.str-el