Title: Surface phase metastability during Langmuir evaporation: dataset

Citation
Hannikainen K, Gomez D, Pereiro J, et al. (2019). Surface phase metastability during Langmuir evaporation: dataset. Cardiff University. http://doi.org/10.17035/d.2019.0085857240


Access Rights: Data is provided under a Creative Commons Attribution (CC BY 4.0) licence
Access Method: Click to email a request for this data to opendata@cardiff.ac.uk

Dataset Details
Publisher: Cardiff University
Date (year) of data becoming publicly available: 2019
Data format: .dat, .xlsx, .png, .m
Software Required: Uview - Elmitec Low Energy Electron Microscope software (Files can be opened with STM/AFM software such as ImageJ or WSXM).
MATLAB - Montecarlo simulations provided as MATLAB code.

Estimated total storage size of dataset: Less than 10 gigabytes
DOI: 10.17035/d.2019.0085857240

Description

We have directly imaged the spontaneous formation of metastable surface phase domains on GaAs(001) during Langmuir evaporation. Eventually, these metastable phases transform to the thermodynamically stable parent phase, producing a dynamic phase coexistence with a temperature dependent, time-averaged coverage. Monte Carlo simulations are used to identify the key kinetic processes and investigate the interplay between phase metastability and evolving surface morphology. This is used to explain the measured temperature dependence of the time-averaged coverage.

Data associated with the 5 figures of the article:

Fig.1 - The figure is a sequence of 6 images obtained using Low Energy Electron Microscopy (LEEM), showing the fundamental mechanism of metastability. The data is raw data (files produced by the Low Energy Electron Microscope) in the original format. The files can be opened with ImageJ (we attach .png showing the required settings after clicking File>Import>Raw). We also attach a .png indicating the region of the full image that is zoomed in the article's figures.

Fig.2 - This figure is just an illustration and does not represent experimental data.

Fig.3 - Experimental and Monte Carlo datasets of the time-averaged (6x6) coverage, in percentage points, as a function of temperature. The second dataset shows the instantaneous (6x6) coverage as a function of time for the Monte Carlo simulation at T=592C.

Fig. -4 Measured rates of the key kinetic processes used in the Monte Carlo model, as a function of temperature. These are: rate Jw of lochkeim formation on c(8x2), rate Jb of lochkeim formation on (6x6), step velocity v, rate ϱ of c(8x2) nucleation on (6x6). The dataset shows the natural logarithm of the rates, as a function of the inverse of kT (i.e., 1/kT, where k is the Boltzmann constant and T is temperature), with the rates measured in microns^(-2)seconds^(-1) (in microns/second for the step velocity).

Fig-5. The figure shows Low Energy Electron Microscopy images and Monte Carlo simulation snapshots of the surface at three different temperatures. The data of the experimental images is provided in raw data format from the Elmitec U-View program (files produced by the Low Energy Electron Microscope). It can be visualized using ImageJ, as that of Fig. 1. The data of the Monte Carlo simulations is provided as MatLab code.

Research results based upon these data are published at http://doi.org/10.1103/PhysRevLett.123.186102



Keywords

Mirror electron microscopy

Related Projects

Last updated on 2019-06-11 at 16:31