arXiv subjects

D. M. Deaven

Publications and source records attributed to D. M. Deaven.

3 recordsLinked to original sources

arXiv1996

Incomplete melting of the Si(100) surface from molecular-dynamics simulations using the Effective-Medium Tight-Binding model

We present molecular-dynamics simulations of the Si(100) surface in the temperature range 1100-1750K. To describe the total energy and forces we use the Effective-Medium Tight-Binding model. The defect-free surface is found to melt at the bulk melting point, which we determine to be 1650 K, but for a surface with dimer vacancies we find a pre-melting of the first two layers 100 K below the melting point. We show that these findings can rationalize recent experimental studies of the high temperature Si(100) surface.

cond-mat↗

arXiv1995

Molecular geometry optimization with a genetic algorithm

We present a method for reliably determining the lowest energy structure of an atomic cluster in an arbitrary model potential. The method is based on a genetic algorithm, which operates on a population of candidate structures to produce new candidates with lower energies. Our method dramatically outperforms simulated annealing, which we demonstrate by applying the genetic algorithm to a tight-binding model potential for carbon. With this potential, the algorithm efficiently finds fullerene cluster structures up to ${\rm C}_{60}$ starting from random atomic coordinates.

mtrl-th↗

arXiv1993

Holons in Chiral Spin-Liquids: Statistics and Pairing

We study Gutzwiller-projected variational wavefunctions for charged, spinless holon excitations in chiral spin liquids. We find that these states describe anyons, with a statistical phase $Φ_s$ that is continuously adjustable between $0$ and $π/2$, depending on a variational parameter. The statistical flux attached to each holon is localized to within a lattice constant. By diagonalizing the effective Hamiltonian for charge motion in our variational basis we obtain a two-holon pair state. This two-holon state has large overlap with a two-hole state whose relative wavefunction has $d$-wave symmetry and breaks time-reversal and parity.

cond-mat↗