Shumway Research Group

Department of PhysicsArizona State UniversityTempe • AZ
Research in Path Integral Simulations, Quantum States of Matter, and Nanoscale Electronics

Nanostructure Simulation and Modeling Programs

These are some of the codes we use in our research program that we are making freely available for download under GNU GPL. While we strive for well-documented, high-quality, user-friendly programs, these are works in progress. We are posting these open source developmental versions to the web in the hopes that they are of use to other scientists, especially beginning researchers. Feedback is welcome, but please understand that real user-friendly codes are still a few years away. (See "Lists of Web Resources" for links to other open-source projects.)

NSF Work supported by NSF Grant DMR 02-39819.

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Path Integral Simulation Code

This code, pi, is a general purpose path integral quantum Monte Carlo program. This open-source research code is intended to be well-documented, with reliable implementations of boson and fermion path integrals.

Libraries used: HDF5, libxml2, blitz++, tvmet, lapack, mpi (i.e. mpich or lam-mpi)

Atomic Nanostructure Layout Code

This code, geom, is a simple utility for turning nanostructure descriptions into atomic layout. These atomic positions are common input for several types of quantum dot models, such as tight-binding or empirical pseudopotentials. The user specifies the size, shape, and composition of a coherent III-V or group IV semiconductor heterostructure. Shapes include lens, pyramidal, and conical dots, as well as quantum wells, and may be filled with different alloy or pure materials. Output is an HDF5 file, struct.h5, containing atom positions, chemical identities, lattice indexing, and neighbor tables. The object-oriented design makes it easy for users to add new shapes and materials to this utility.

Strain Relaxation Code

This program, relax, uses a conjugate-gradient algorithm to relax atomic positions in coherently strained semiconductor nanostructures. A typical simulation of millions of atoms in and around an embeded quantum dot runs in a few hours on a typical PC. Input is an HDF5 file, struct.h5, containing the atomic positions, identities, and neighbor tables. The program output is the relaxed atomic positions in the same HDF5 format as the input file, suitable for input into an atomistic electronic structure model. Also calculates stress for each atom.

Simulation Data Analysis Tool

This Java program, dataspork, is a graphical tool for analyzing Monte Carlo data. It was developed at the University of Illinois, and is distributed there as part of the MCC software archive. We still use and maintain a version, and we may post some updates on our website in cooperation with David Ceperley and the MCC. Ceperley maintain's some online documentation.