Table of Contents

• Table of Contents
• Introduction
• surface-pd Framework
• How to cite
• Documentation
• Installation
• Using surface-pd

Introduction

The surface degradation of layered transition metal (TM) oxides and other related cathode compositions has been characterized extensively in experiments. However, how the reactions take place on the cathode surface and how surface reconstructions form on the atomic scale remains unclear. The surface phase diagram as a function of state of charge and temperature can offer insights into atomic-scale processes that are challenging to probe experimentally.

To construct the surface phase diagram, slab models with different surface compositions need to be created. The surface phase diagram shown on the left above only has four phases that are predicted to be stable in the range of 0 to 5 V and 0 to 1500 K. However, behind the most stable phases shown on the surface phase diagram, hundreds/thousands meta-stable phases should also be calculated. The figure shown above on the right illustrates how the three-dimensional surface phase diagram looks like when "all" enumerated slab models are considered.

surface-pd Framework

This package uses the method developed in the enumlib code. In contrast to the conventional enumlib code, we apply systematic enumeration to only part of the slab model, creating vacancies on the surface. By taking advantage of the inherent inversion symmetry center of the slab models, the top surface is symmetrized to the bottom surface, i.e., a symmetrically equivalent modification is introduced at the bottom of the slab models. The flowchart below shows the framework of the surface enumeration.

How to cite

If you have used surface-pd, please cite the GitHub repository:

@software{surface_pd,
  author = {Li, Xinhao and Urban, Alexander},
  title = {surface-pd: Surface Phase Diagram Generator},
  url = {https://github.com/urban-group/surface-pd},
  version = {1.0.0},
  year = {2024}
}

Or in text format:

Li, X., & Urban, A. (2024). surface-pd: Surface Phase Diagram Generator (Version 1.0.0) [Computer software]. https://github.com/urban-group/surface-pd

Thank you for your interest.

Documentation

If you want to learn more about surface-pd, please find the user manual.

Or please contact: Xinhao Li (xinhao.li@columbia.edu) and Alex Urban (a.urban@columbia.edu)

Installation

surface-pd is a Python 3 package and the stable version can be installed via pip.

$ pip install surface-pd

Using surface-pd

Please refer to the official surface-pd documentation for tutorials and examples.