μ
Chemical Potential LabBINARY & TERNARY STABILITY · DFT WORKSPACE
VERSION 11

Chemical-potential stability diagrams.

Enter a two- or three-element compound and a consistent phase dataset to choose conditions for defect calculations.

Illustrative exampleThese energies demonstrate the method. Replace them with a consistent DFT dataset before research use.
CHEMICAL-POTENTIAL SPACE

SrTiO₃ stability region

Calculating

2D shows X versus Y. Z is calculated from the host equality. Selecting an assigned element swaps the two axes.

Show on plot

Exports follow label and selected-point visibility and omit the captions below the diagram. PNG: 2400 pixels wide, 8 inches at 300 dpi.

03

Selected condition

Interior

Boundary vertices / endpoints

Derived inequalities

Every enabled phase obeys Σ nᵢ Δμᵢ ≤ ΔHf. The host equality eliminates one potential; all elemental Δμᵢ ≤ 0.

Method & DFT workflow

This is a zero-temperature, bulk phase-stability model for an entered set of competing phases. Its allowed region is conditional on that set being complete.

Binary hosts have one independent chemical potential: a ΔμA + b ΔμB = ΔHf. Their stable host region is an interval, shown as a number line or a line segment in the two-potential plane. The other potential is calculated automatically. A finite binary interval is a normal stability window; only a collapsed point is marginal.

In the 3D phase-faces view, each surface satisfies its phase equality Σ nᵢ Δμᵢ = ΔHf and every other phase inequality, including the host. The pink surface is the host stability polygon. Display bounds clip otherwise unbounded surfaces; the bounding box is not a thermodynamic phase. Clicking another phase reports its chemical potentials separately from the host defect condition.

In total-energy mode, ΔHf = Ecell / formula units − Σ nᵢ μᵢ⁰. In eV/atom mode, the energy is first multiplied by the number of atoms in the entered formula. All reported chemical potentials are in eV/atom.

For a defect, with nᵢ positive for atoms added: Eᶠ = Edefect − Ehost − Σ nᵢ μᵢ + q(EF + EVBM) + Ecorr. Use absolute μᵢ = μᵢ⁰ + Δμᵢ with raw total-energy differences. Charge corrections and Fermi-level dependence are outside this prototype.

Include relevant elemental, binary, ternary, and polymorph competitors. Direct OUTCAR/vasprun.xml parsing, temperature/pressure conversion, and automatic phase discovery are not included. No numerical DFT accuracy is implied by the displayed decimal places.

Workflow inspired by inspection of Chesta’s interface resources and sample-file structure. Independently written solver and interface; no Chesta code, data, or assets are bundled.

Background: Materials Project: chemical-potential diagrams.

ZnSb₂O₄ · HSE RECONSTRUCTION

Fig. 1 · surrounding phase faces

ZnO, Sb₂O₃, Sb₂O₅ and Sb-metal faces surround the pink ZnSb₂O₄ host polygon. These are fixed reconstructions of the paper inputs; editing the calculator does not change these images.

ZnSb2O4 HSE reconstruction with surrounding competing-phase faces, pink host stability polygon, and a corresponding 2D projection
Open full-size SVGDownload SVG

New system

Use any compound with two or three elements. Start with its formation energy, then add competing phases or switch to DFT total energies in the workspace. Save your current session first if you want to keep it.

Negative values describe formation from the elemental references. No example competing phases will be carried over.