An accelerated algorithm for full band electron–phonon scattering rate computation

Computing scattering rates of electrons and phonons stands at the core of studies of electron transport properties. In the high field regime, the interactions between all electron bands with all phonon bands need to be considered. This full band interaction implies a huge computational burden in calculating scattering rates. In this study, a new accelerated algorithm is presented for this task, which speeds up the computation by two orders of magnitude (100 times) and dramatically simplifies the coding. At the same time, it visually demonstrates the physical process of scattering more clearly.Program summaryProgram title: Scattering_band_by_bandCatalogue identifier: AEUH_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEUH_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 22914No. of bytes in distributed program, including test data, etc.: 5785964Distribution format: tar.gzProgramming language: Matlab.Computer: All.Operating system: All.RAM: Depends on problem, ∼kB to MBClassification: 16.5.Nature of problem:Electron–phonon scattering is a fundamental problem in studying electron transport in condensed matters. There are situations where the scattering rates need to be updated frequently during a simulation, e.g. when hot phonon effects are considered. The speed of scattering calculation is very important in such cases.Solution method:In searching for possible scattering events, we propose here a band-by-band method, instead of the traditional point by point method. The whole calculation is parallelized in this sense and dramatically accelerated. Moreover, we proposed a representation method for all scattering mechanisms, which greatly simplified the coding task. Also, the additional animation part of this program demonstrates many insights into the scattering process.Restrictions:To use the code directly, electron band and phonon band should have the same mesh size. In other words, for each phonon band and electron band, they should have the same number of data points.Additional comments:If high speed is desired, it is best to turn off the animation function.Running time:Running time depends on the problem size. For the example used in this paper, it takes about 144 seconds by 1 CPU on Dell PowerEdge 610 (A dual quad core server with CPU frequency of 3.0 GHz).