Materials Project Formation Energy Distribution¶

!pip install pymatviz

import pandas as pd
import plotly.express as px
import plotly.io as pio
from pymatgen.ext.matproj import MPRester

from pymatviz import count_elements, ptable_heatmap_plotly
from pymatviz.enums import Key


__author__ = "Janosh Riebesell"
__date__ = "2022-08-11"

pio.renderers.default = "png"

MP_API_KEY = "your Materials Project API key"
e_form_col = "formation_energy_per_atom"
fields = [Key.mat_id, Key.formula_pretty, e_form_col, "energy_type"]

e_form_all_mp = MPRester(use_document_model=False).thermo.search(
    fields=fields,
    thermo_types=None,
    # thermo_types=["GGA_GGA+U_R2SCAN"],
    chunk_size=200,
)

df_e_form = pd.DataFrame(e_form_all_mp).set_index(Key.mat_id)
df_e_form = df_e_form.rename(columns={"formula_pretty": Key.formula})
df_e_form.head(10)

# cache MP data
# %store df_e_form

# load cached MP data
# %store -r df_e_form

df_e_form.energy_type.value_counts()

df_e_form_gga_only = df_e_form.query("energy_type in ('GGA', 'GGA+U')")
expected = 121_555
if len(df_e_form_gga_only) != expected:
    print(f"{expected=} GGA & GGA+U entries, got {len(df_e_form_gga_only)}")

for energy_type, df_e_type in [
    *df_e_form.groupby("energy_type"),
    ("GGA & GGA+U", df_e_form_gga_only),
]:
    fig = ptable_heatmap_plotly(df_e_type[Key.formula])
    title = f"{len(df_e_type):,} {energy_type} entries"
    fig.layout.title = dict(text=title, x=0.4, y=0.94, font=dict(size=20))
    fig.show()

labels = {
    "formation_energy_per_atom": "Formation Energy [eV/atom]",
    "count": "Number of Entries",
}
for energy_type, df_e_type in [
    *df_e_form.groupby("energy_type"),
    ["all together", df_e_form],
    ["GGA & GGA+U (no r2SCAN)", df_e_form_gga_only],
]:
    fig = px.histogram(
        df_e_type.query(f"-5 < {e_form_col} < 5"),
        x=e_form_col,
        nbins=150,
        range_x=(-5, 3),
        labels=labels,
    )
    title = f"{energy_type}: {len(df_e_type):,} entries"
    fig.layout.title = dict(text=title, x=0.5)

    # add vertical line at valley of GGA & GGA+U bimodal distribution
    if energy_type == "GGA & GGA+U (no r2SCAN)":
        e_form_valley = -1.35
        anno = dict(
            text=f"{e_form_valley} eV/atom",
            font=dict(size=14, color="orange"),
            xshift=10,
        )
        fig.add_vline(
            e_form_valley, line=dict(color="orange", dash="dash"), annotation=anno
        )

    fig.show()

for comparator, label in ((">", "higher"), ("<=", "lower")):
    df_query = df_e_form_gga_only.query(f"{e_form_col} {comparator} {e_form_valley}")
    fig = ptable_heatmap_plotly(df_query[Key.formula])
    title = (
        f"Elements in {len(df_query):,} {label} mode MP entries "
        f"({comparator} {e_form_valley} eV/atom)<br><br>"
    )
    title += "<br>".join(
        f"{e_type}: {cnt:,}"
        for e_type, cnt in df_query.energy_type.value_counts().items()
    )

    fig.layout.title = dict(text=title, x=0.4, y=0.94)
    fig.show()

for comparator, label in ((">", "higher"), ("<=", "lower")):
    sub_formulas = df_e_form_gga_only.query(
        f"formation_energy_per_atom {comparator} {e_form_valley}"
    ).formula
    elem_counts = count_elements(sub_formulas)
    fig = px.bar(elem_counts.nlargest(20))
    title = f"{label.title()} mode {comparator} {e_form_valley} eV/atom"
    fig.layout.update(title=dict(text=title, x=0.5), showlegend=False)
    fig.show()