Programs in Physics & Physical Chemistry
|[Licence| Download | New Version Template] acgs_v1_0.gz(54 Kbytes)|
|Manuscript Title: TRSS: a new version of program TRS for a different geometry.|
|Authors: J. Schmitz, H.-R. Trebin, U. Rossler|
|Program title: TRSS|
|Catalogue identifier: ACGS_v1_0|
Distribution format: gz
|Journal reference: Comput. Phys. Commun. 69(1992)369|
|Programming language: Fortran.|
|Computer: VAX II/GPX.|
|Operating system: VMS 4.6, TOS, CMSL 4.421.|
|Word size: 32|
|Keywords: Solid state physics, Surface, Narrow gap Semiconductors, Zincblende lattice, Landau levels, Uniaxially stress parallel to magnetic field, Effective hamiltonian, Invariant expansion, Eightfold space of Valence band and lowest Conduction band, Normal and inverted Bands, Energy eigenvalues, Eigenvectors, Direct inter and Intraband dipole Transitions, Oscillator strengths, Gamma-point,  and  crystal axis, Uniaxial stress Perpendicular To magnetic field.|
Nature of problem:
An effective Hamiltonian constructed by invariant expansion is used to calculate Landau levels and wave functions in narrow-gap semiconductors with a zincblende or diamond lattice under uniaxial stress. It is based on an eightfold space of uppermost valence and lowest conduction bands at the center of the Brillouin zone and its vicinity. The wave functions are further used to calculate the oscillator strengths of direct inter- and intraband dipole transitions. Thus program TRSS is a valuable tool for the experimentalist to analyze quantum resonances measured in semiconductors.
The matrix elements of the Hamiltonian are set up one by one according to the equations derived from the theory. Then the resulting matrix is diagonalized using Householder's reduction followed by the QL method. Energy eigenvalues and eigenvectors are further used in calculation of oscillator strengths.
The dimensions of arrays are set to include Landau levels with oscillator quantum number up to na <= 39. Adaptions are easily made. Due to the limitations in the Kane-modell and the underlying perturbation theory the program is only suitable for eigenstates in the vicinity of the Gamma-point. Transitions are restricted to direct dipole transitions. All calculations are based on a geometry with magnetic field parallel to the  crystal axis and uniaxial stress applied parallel to the  crystal axis.
TRSS contains a subroutine which clears the screen of the terminal before displaying a new page of text. This action is not essential to the operation of the program and may be entirely omitted. In order to preserve the intended screen display it must be adapted to the specific device used.
Execution times depend strongly on the maximum Landau oscillator quantum number and the number of transitions chosen. The test run described in the Long write-up requires 25.68 seconds on the VAX II/GPX, 2.06 seconds, on the Comparex 8/89 and 11 minutes 17 seconds on the Atari 1040st.
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