213 citations · 1.3k across the 34 of their papers we have counts for
19 papers · 1 filter
Anisotropic Kondo screening induced by spin-orbit coupling in quantum wires
E. Vernek, G. B. Martins, R. Zitko
Using the numerical renormalization group (NRG) method we study a magnetic impurity coupled to a quantum wire with Rashba and Dresselhaus spin-orbit coupling (SOC) in an external m…
Reentrant Kondo effect in a quantum impurity coupled to a metal-semiconductor hybrid contact
G. Diniz, G. S. Diniz, G. B. Martins +1
Using NRG, we show that a system containing a quantum impurity (QI), strongly coupled to a semiconductor (gap ) and weakly coupled to a metal, displays a 'reentrant' Kondo sta…
The crossover and spin filter properties of a double quantum dot nanosystem
V. Lopes, R. A. Padilla, G. B. Martins +1
The crossover, driven by an external magnetic field , is analyzed in a capacitively-coupled double-quantum-dot device connected to independent leads. As one contin…
Spatial structure of correlations around a quantum impurity at the edge of a two-dimensional topological insulator
Andrew Allerdt, Adrian E. Feiguin, George B. Martins
We calculate exact zero-temperature real space properties of a substitutional magnetic impurity coupled to the edge of a zigzag silicene-like nanoribbon. Using a Lanczos transforma…
Kondo versus indirect exchange: the role of the lattice and the actual range of RKKY interactions in real materials
Andrew Allerdt, C. A. Busser, G. B. Martins +1
Magnetic impurities embedded in a metal interact via an effective Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling mediated by the conduction electrons, which is commonly assumed to b…
Polarized currents and spatial separation of Kondo state: NRG study of spin-orbital effect in a double QD
E. Vernek, C. A. Busser, E. V. Anda +2
A double quantum dot device, connected to two channels that only see each other through interdot Coulomb repulsion, is analyzed using the numerical renormalization group technique.…
RPA Analysis of a Two-orbital Model for the BiS2-based Superconductors
George Martins, Adriana Moreo, Elbio Dagotto
The random-phase approximation (RPA) is here applied to a two-orbital model for the BiS2-based superconductors that was recently proposed by Usui et al., arXiv:1207.3888. Varying t…
The spatial range of the Kondo effect: a numerical analysis
C. A. Büsser, G. B. Martins, L. Costa Ribeiro +3
The spatial length of the Kondo screening is still a controversial issue related to Kondo physics. While renormalization group and Bethe Anzats solutions have provided detailed inf…
A Novel Approach to Study Highly Correlated Nanostructures: The Logarithmic Discretization Embedded Cluster Approximation
E. V. Anda, G. Chiappe, C. A. Busser +4
This work proposes a new approach to study transport properties of highly correlated local structures. The method, dubbed the Logarithmic Discretization Embedded Cluster Approximat…
Static Holes in the Geometrically Frustrated Bow Tie Ladder
George B. Martins, Wolfram Brenig
We investigate the doping of a geometrically frustrated spin ladder with static holes by a complementary approach using exact diagonalization and quantum dimers. Results for thermo…
Transport through quantum dots: A combined DMRG and cluster-embedding study
F. Heidrich-Meisner, G. B. Martins, C. A. Busser +5
The numerical analysis of strongly interacting nanostructures requires powerful techniques. Recently developed methods, such as the time-dependent density matrix renormalization gr…
Hole-pair symmetry and excitations in the strong-coupling extended t-Jz model: competition between d-wave and p-wave
R. M. Fye, G. B. Martins, E. Dagotto
We analytically calculate the ground state pairing symmetry and excitation spectra of two holes doped into the half-filled t-t'-t"-Jz model in the strong-coupling limit (Jz>>|t|,|t…
Superconductivity in the two-dimensional t-J model
S. Sorella, G. B. Martins, F. Becca +4
Using computational techniques, it is shown that pairing is a robust property of hole doped antiferromagnetic (AF) insulators. In one dimension (1D) and for two-leg ladder systems,…
Doped Stripes in Models for the Cuprates Emerging from the One-hole Properties of the Insulator
G. B. Martins, C. Gazza, J. C. Xavier +2
The extended and standard t-J models are computationally studied on ladders and planes, with emphasis on the small J/t region. At couplings compatible with photoemission results fo…
Indications of Spin-Charge Separation in the 2D Extended t-J Model
George B. Martins, Robert Eder, Elbio Dagotto
The 2D extended model is studied computationally in a broad region of parameter space, motivated by recent photoemission experiments for the undoped cuprate $\rm Ca_2 Cu…
Hole-Density Evolution of the One-Particle Spectral Function in Doped Ladders
George B. Martins, Claudio Gazza, Elbio Dagotto
The spectral function of doped ladders is presented on clusters with up to sites at zero temperature applying a recently developed technique tha…
Enhancement of Antiferromagnetic Correlations Induced by Nonmagnetic Impurities: Origin and Predictions for NMR Experiments
Markus Laukamp, George Balster Martins, Claudio J. Gazza +5
Spin models that have been proposed to describe dimerized chains, ladders, two dimensional antiferromagnets, and other compounds are here studied when some spins are replaced by sp…
High-field Electron Spin Resonance of Cu_{1-x}Zn_{x}GeO_{3}
A. K. Hassan, L. A. Pardi, G. B. Martins +2
High-Field Electron Spin Resonance measurements were made on powder samples of Cu_{1-x}Zn_{x}GeO_{3} (x=0.00, 0.01, 0.02, 0.03 and 0.05) at different frequencies (95, 110, 190, 220…
Local Enhancement of Antiferromagnetic Correlations by Nonmagnetic Impurities
George Balster Martins, Markus Laukamp, Jose Riera +1
The local enhancement of antiferromagnetic correlations near vacancies observed in a variety of spin systems is analyzed in a single framework. Variational calculations suggest tha…