0-9
A
- Ab initio Molecular Dynamics (AIMD)
- Molecular Dynamics (MD) where forces come from Density Functional Theory (DFT) at every time step. Lets you simulate finite-temperature behavior (melting, diffusion, reactions) without an empirical force field.
- Acoustic Sum Rule (ASR)
- Constraint that the three acoustic phonon modes go to zero frequency at Γ (gamma). Enforcing ASR fixes small numerical drifts in phonon calculations.
- Atom
- Will Be explained
B
- Bader Charge Analysis
- Partitions total charge density into atomic basins to estimate charge transfer and bonding character.
- Band
- Will Be Explained
- Band Folding
- In supercells, bands appear “multiplied” (folded). Unfolding maps them back to the primitive Brillouin Zone to interpret dispersion cleanly.
- Band Gap (Direct/Indirect)
- Energy difference between valence-band maximum and conduction-band minimum. Direct gaps allow vertical optical transitions; indirect gaps need a phonon.
- Band Structure E(k)
- Energy of electronic state vs crystal momentum. The slope gives carrier group velocity; curvature gives effective mass.
- Berry Phase (Polarization)
- Modern theory of polarization using phases of Bolch state across k-space. Underlines ferroelectric polarization and related transport phenomena
- Boltzmann Transport (BoltzTraP)
- Uses DFT bands to compute conductivity (σ), Seebeck(S), and electronic thermal conductivity (κ_e) under a relaxation-time approximation.
- Born Effective Charge (Z*)
- Dyanmic charge measuring the coupling between atomic displacements and macroscopic electric field. Needed for IR intensities and LO-TO splitting.
- Brillouin Zone (BZ)
- The primitive cell of reciprocal space. All k-space integrals and band paths are taken inside the first BZ.
C
- Chemical Potential(μ)
- Energy cost to add/remove a particle (atom, electron). Sets resorvoirs for defect formation energies and surface thermodynamics.
- Core – Level Shift
- Change in core binding energies due to environment. Computed via ΔSCF or initial – state approximations; used to interpret XPS
- Cutoff Energy
- Maximum plane-wave kinetic energy included in the basis. Higher Cutoff Energy → more accuracy but slower computation. Converge energies with respect to Cutoff Energy.
D
- Density Functional Perturbation Theory (DFPT)
- Linear response DFT for phonons, dielectric tensors, Born charges, electron-phonon couplings without finite difference
- Density Functional Theory
- Will Be Explained
- Density of States (DOS)
- DOS explains that how many electronic states exist at a specific energy E.
- DFT+U
- Adds a Hubbard-U correction for localized d/f states to fix over-delocalization in semilocal DFT. U can be chosen by literature or linear-response
- Dielectric Function
- Frequency – dependent optical response. ε(ω)=ε₁+iε₂ From ε you get refractive index (n,k), Reflectivity R(ω), absorption α(ω), and loss function −Im[1/ε].
- Dipole Correction (Slabs)
- Removes artificial fields in asymmetric slabs by adding a planar dipole. Stabilizes work-function and surface – energy calculations.
- Drude
- Will Be Explained
- Drude Model
- Classical intraband (free-carrier) contribution to optics in metals. Needed for IR/THz reflectivity.
E
- Effective Mass
- Measures band curvature near extrema: larger curvature → lighter carriers → potentially higher mobility. Can be direction-dependent
- Electron
- Will Be Explained
- Exchange Corelation
- Will Be Explained
F
G
H
I
- Interface
- Will Be Explained
J
K
L
M
N
- NPT
- Will Be Explained
- NVE
- Will Be Explained
- NVT
- Will Be Explained
O
P
- Plane Wave
- Will Be Explained
- Plasmon
- Will Be Explained
- Projected Density of States (PDOS)
- PDOS breaks DOS into atomic/orbital contributions to see who “owns” the states.
Q
R
S
- Smearing
- Will Be Explained
- Surface
- Will Be Explained
T
U
V
W
- Wave Function
- Will Be Explained
- Work Function
- Will Be Explained
X
Y
Z