potential-analysis

name	potential-analysis
description	Potential Analysis (3 sub-skills: macroscopic-average, planar-average, work-function)

Potential Analysis

Overview

This skill group covers electrostatic potential analysis from first-principles calculations. It provides workflows for extracting, averaging, and interpreting the electrostatic potential from Quantum ESPRESSO and VASP outputs. These analyses are essential for work function calculations, band alignment at interfaces, and understanding interface dipoles.

All workflows correspond to VASPKIT menu 42 (tasks 420--430).

Sub-Skills

Sub-Skill	Directory	Description
Work Function	work-function/	Calculate work function from planar-averaged electrostatic potential. Vacuum level minus Fermi energy. QE: pp.x + average.x. VASP: LOCPOT parsing.
Planar Average	planar-average/	Planar-average and macroscopic-average of charge density and potential along a chosen axis. QE: pp.x + average.x. VASP: LOCPOT/CHGCAR parsing. Line profiles along specified paths.
Macroscopic Average	macroscopic-average/	Double (macroscopic) averaging technique for interface dipoles, band offsets, and heterojunction band alignment.

When to Use

• work-function/ -- You need the work function of a surface slab (vacuum level minus Fermi energy).
• planar-average/ -- You need 1D profiles of the electrostatic potential or charge density averaged over planes perpendicular to a slab normal or interface direction.
• macroscopic-average/ -- You need smooth macroscopic averages for band alignment at heterojunctions, interface dipole determination, or Schottky barrier estimation.

General Prerequisites

• Quantum ESPRESSO 7.5 (pw.x, pp.x, average.x)
• Python packages: pymatgen, ase, numpy, scipy, matplotlib
• A converged slab calculation with sufficient vacuum (typically 15--20 Angstrom)
• For VASP workflows: LOCPOT and/or CHGCAR files from a slab calculation