Mizuno, M., Kim, Eugene H., Martins, G. B.
Transport through carbon nanotube (CNT) quantum dots (QDs) in a magnetic field is discussed. The evolution of the system from the ultraviolet to the infrared is analyzed; the strongly correlated (SC)...
The spatial range of the Kondo effect: a numerical analysis (2009)
Büsser, C. A., Martins, G. B., Ribeiro, L. Costa, Vernek, E., Anda, E. V., Dagotto, E.
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 information about the...
Vernek, E., Busser, C. A., Martins, G. B., Anda, E. V., Sandler, N., Ulloa, S. E.
Transport properties of an interacting triple quantum dot system coupled to three leads in a triangular geometry has been studied in the Kondo regime. Applying mean-field finite-U slave boson and...
Heidrich-Meisner, F., Feiguin, A. E., Busser, C. A., Martins, G. B., Anda, E. V., ...
We apply the adaptive time-dependent Density Matrix Renormalization Group method (tDMRG) to the study of transport properties of quantum-dot systems connected to metallic leads. Finite-size effects...
Anda, E. V., Chiappe, G., Busser, C. A., Davidovich, M. A., Martins, G. B., Heidrich-Meisner, F., ...
This work proposes a new approach to study transport properties of highly correlated local structures. The method, dubbed the Logarithmic Discretization Embedded Cluster Approximation (LDECA),...
Diagonalization in Reduced Hilbert Spaces using a Systematically Improved Basis (2007)
E. Dagotto, G. B. Martins, J. Piekarewicz, J. Riera, J. R. Shepard
A method is proposed to improve the accuracy of approximate techniques for correlated electrons that use reduced Hilbert spaces. As a first step, the method involves a change of basis that...
Transport through quantum dots: A combined DMRG and cluster-embedding study (2007)
Heidrich-Meisner, F., Martins, G. B., Busser, C. A., Al-Hassanieh, K. A., Feiguin, A. E., Chiappe, G., ...
The numerical analysis of strongly interacting nanostructures requires powerful techniques. Recently developed methods, such as the time-dependent density matrix renormalization group (tDMRG)...
New Numerical Results Indicate a Half-Filling SU(4) Kondo State in Carbon Nanotubes (2006)
Numerical calculations simulate transport experiments in carbon nanotube quantum dots (P. Jarillo-Herrero et al., Nature 434, 484 (2005)), where a strongly enhanced Kondo temperature T_K ~ 8K was...
Martins,G. B., Büsser,C. A., Al-Hassanieh,K. A., Anda,E. V., Moreo,A., Dagotto,E.
Numerical calculations are shown to reproduce the main results of recent experiments involving nonlocal spin control in nanostructures (N. J. Craig et al., Science 304, 565 (2004)). In particular,...
Martins, G. B., Busser, C. A., Al-Hassanieh, K. A., Anda, E. V., Moreo, A., Dagotto, E.
Numerical calculations are shown to reproduce the main results of recent experiments involving nonlocal spin control in nanostructures (N. J. Craig et al., Science 304, 565 (2004)). In particular,...
Electron Transport through a Molecular Conductor with Center-of-Mass Motion (2005)
Al-Hassanieh, K. A., Büsser, C. A., Martins, G. B., Dagotto, E.
The linear conductance of a molecular conductor oscillating between two metallic leads is investigated numerically both for Hubbard interacting and noninteracting electrons. The molecule-leads...
Prediction of Ferromagnetic Correlations in Coupled Double-Level Quantum Dots (2004)
Martins, G. B., Busser, C. A., Al-Hassanieh, K. A., Moreo, A., Dagotto, E.
Numerical results are presented for transport properties of two coupled double-level quantum dots. The results strongly suggest that under appropriate circumstances the dots can develop a novel...
Interference Effects in the Conductance of Multi-Level Quantum Dots (2004)
Büsser, C. A., Martins, G. B., Al-Hassanieh, K. A., Moreo, Adriana, Dagotto, Elbio
Using exact-diagonalization techniques supplemented by a Dyson equation embedding procedure, the transport properties of multilevel quantum dots are investigated in the Kondo regime. The conductance...
Albuquerque, A. F., Martins, G. B.
Exact Diagonalization calculations are presented for the t-J model in the presence of a uniform magnetic field. Results for 2xL ladders (L=8,10,12) and 4x4 square clusters with 1 and 2 holes indicate...
Fye, R. M., Martins, G. B., Dagotto, E.
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'|,|t"|). In...
Superconductivity in the two-dimensional t-J model (2002)
Sorella, Sandro, Martins, G.B., Becca, Federico, Gazza, C., Capriotti, Luca, Parola, Alberto, ...
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, a BCS-like...
Superconductivity in the two-dimensional t-J model (2001)
Sorella, S., Martins, G. B., Becca, F., Gazza, C., Capriotti, L., Parola, A., ...
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, a BCS-like...
Anomalous NMR Magnetic Shifts in CeCoIn_5 (2001)
Curro, N. J., Simovic, B., Hammel, P. C., Pagliuso, P. G., Martins, G. B., Sarrao, J. L., ...
We report ^{115}In and ^{59}Co Nuclear Magnetic Resonance (NMR) measurements in the heavy fermion superconductor CeCoIn_5 above and below T_c. The hyperfine couplings of the In and Co are anisotropic...
Martinho, H., Moreno, N. O., Sanjurjo, J. A., Rettori, C., Garcia-Adeva, A. J., Huber, D. L., ...
The $T$-dependence (2- 400 K) of the electron paramagnetic resonance (EPR), magnetic susceptibility, $\chi (T)$, and specific heat, $C_{v}(T)$, of the $normal$ antiferromagnetic (AFM) spinel...
Martins, G. B., Xavier, J. C., Gazza, C., Vojta, M., Dagotto, E.
The recently discussed tendency of holes to generate nontrivial spin environments in the extended two-dimensional t-J model (G. Martins, R. Eder, and E. Dagotto, Phys. Rev. B{\bf 60}, R3716 (1999))...
Stripes in the Ising Limit of Models for the Cuprates (2000)
Martins, G. B., Gazza, C., Dagotto, E.
The hole-doped standard and extended t-J models on ladders with anisotropic Heisenberg interactions are studied computationally in the interval $0.0 \leq \lambda \leq 1.0$ ($\lambda=0$, Ising;...
Martins, G. B., Gazza, C., Xavier, J. C., Feiguin, A., Dagotto, E.
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 for undoped cuprates,...
Structural effects in the EPR spectra of Ni3+ in La2Ni0.5Li0.5O4 (2000)
Urbano, R R, Rettori, C, Oseroff, S B, Martins, G B, Fisk, Z, Pagliuso, P G, ...
Dagotto, E., Martins, G. B., Riera, J., Malvezzi, A. L., Gazza, C.
A method is proposed to improve the accuracy of approximate techniques for strongly correlated electrons that use reduced Hilbert spaces. As a first step, the method involves a change of basis that...
High-field Electron Spin Resonance of Cu_{1-x}Zn_{x}GeO_{3} (1997)
Hassan, A. K., Pardi, L. A., Martins, G. B., Cao, G., Brunel, L-C.
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, 330 and 440 GHz)...