• Publications
  • Influence
Density-matrix electronic-structure method with linear system-size scaling.
  • Li, Nunes, Vanderbilt
  • Physics, Medicine
  • Physical review. B, Condensed matter
  • 15 April 1993
We introduce a method for the solution of the electronic-structure problem in the independent-electron approximation. The method is based upon a variational solution for the density matrix, which isExpand
  • 517
  • 5
Generalization of the density-matrix method to a nonorthogonal basis.
  • Nunes, Vanderbilt
  • Physics, Medicine
  • Physical review. B, Condensed matter
  • 28 July 1994
We present a generalization of the Li, Nunes, and Vanderbilt density-matrix method to the case of a nonorthogonal set of basis functions. A representation of the real-space density matrix is chosenExpand
  • 115
  • 2
  • PDF
Spectroscopic properties and upconversion mechanisms in Er3+-doped fluoroindate glasses.
Fluorindate glasses containing 1,2,3,4 ${\mathrm{ErF}}_{3}$ mol % were prepared in a dry box under argon atmosphere. Absorption, Stokes luminescence (under visible and infrared excitation), theExpand
  • 88
Real-space approach to calculation of electric polarization and dielectric constants.
We describe a real-space approach to the calculation of the properties of an insulating crystal in an applied electric field, based on the iterative determination of the Wannier functions (WF's) ofExpand
  • 55
  • PDF
Fano-like resonant interference in Raman spectra of electronic and LO-vibronic excitations in periodically delta -doped GaAs.
The asymmetry in the one-phonon Raman lines of a Si:GaAs δ-doped doping superlattice is interpreted as a quantum-mechanical interference process in which an incident photon is inelastically scatteredExpand
  • 11
Structure, Barriers, and Relaxation Mechanisms of Kinks in the 90 degrees Partial Dislocation in Silicon.
Kink defects in the 90-degree partial dislocation in silicon are studied using a linear-scaling density-matrix technique. The asymmetric core reconstruction plays a crucial role, generating at leastExpand
  • 49
  • PDF
Plasma heating by two laser fields in the presence of a strong magnetic field.
  • Gargano, Fonseca, Nunes
  • Physics, Medicine
  • Physical review. A, Atomic, molecular, and…
  • 15 February 1990
  • 7
Hydrogenic impurities in a quantum well wire in intense, high-frequency laser fields.
  • Fanyao, Fonseca, Nunes
  • Physics, Medicine
  • Physical review. B, Condensed matter
  • 15 December 1996
  • 94
Transfer and/or breakup modes in the 6He+209Bi reaction near the coulomb barrier
Reaction products from the interaction of 6He with 209Bi have been measured at energies near the Coulomb barrier. A 4He group of remarkable intensity, which dominates the total reaction crossExpand
  • 104
  • PDF
Two-photon absorption spectroscopy of precipitated phases of Eu2+ in KCl single crystals.
Two-photon absorption (TPA) spectroscopy is used to study the aggregation kinetics of ${\mathrm{Eu}}^{2+}$ in KCl single crystals at two different annealing temperatures. The sharpExpand
  • 7
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