NREL, National Renewable Energy Laboratory
NREL MatDB Help Disclaimer

Metadata Standards

The legal values for the metadata :standards: field are shown below.

fere

  • Main purpose: &Delta;H<sub>f</sub> from FERE
  • Fitted elemental reference energies (FERE) definition and values published in DOI 10.1103/PhysRevB.78.245207 and 10.1103/PhysRevB.85.115104.
  • PAW-PBE pseudopotentials (potpaw_PBE only) according to 10.1103/PhysRevB.85.115104, plus Mg_pv, O_s, N_s, F_s.
  • GGA+U method of Dudarev et al. 10.1103/PhysRevB.57.1505 with U = 3 eV for 3d, 4d and 5d transition metals, except Cu and Ag, with U = 5eV. For Zn and Cd without U fere values according to 10.1103/PhysRevB.85.115104. For Zn with U = 6 eV, &mu; = -0.51 eV, and Cd with U = 5 eV, &mu; = +0.19 eV from 10.1103/PhysRevB.78.245207.
  • Energy cutoff, k-point density such to achieve total energy convergence better than about 0.005 eV/atom. For several elements, different pseudopotentials are used, which have slightly different &mu; values, e.g., N/N_s, O/O_s, F/F_s, Mg/Mg_pv.

gwvd

  • Main purpose: Band gap, band-structure, and band-edge shifts.

  • GW scheme according to 10.1103/PhysRevB.87.085112, with scf eigenenergies, but maintaining GGA(+U) wavefunctions, including local field effects in the adiabatic LDA. Pseudopotentials and GGA+U as in standard fere, but using C_s, O_s, N_s, F_s, Mg_pv, Sb_GW, and using GGA+U for Zn and Cd.

  • On-site d-state potential Vd for 3d compounds re-adjusted for VASP version 5.3, compared to 10.1103/PhysRevB.87.085112

    Element

    Vd(eV)

    Cd

    -0.5

    Co

    -1.2

    Cr

    -4.0

    Cu

    -2.4

    Fe

    -0.9

    Mn

    0.0

    Ni

    -0.7

    Sc

    -0.6

    Ti

    -1.3

    V

    -2.8

    Zn

    -1.5

  • VASP 5.3 GW input parameters. For a number NAT of atoms in the unit cell, using a number of 4000/NAT of k-points in the Brillouin zone. NBANDS = 64*NAT ENCUTGW = 200, PRECFOCK = N, NOMEGA = 64, NKRED = 2. </li>

wave

  • Main purpose: GGA(+U) calculation preceding the GW run, using same lattice parameters, same pseudopotentials, same GGA+U parameters, and same NBANDS as in the standard gwvd.

aexp, vexp

These are used together with other standards, e.g., wave, gwvd, ...

  • aexp: Using experimentally determined structure.
  • vexp: After GGA(+U) structural relaxation, perform uniform scaling of lattice parameters to recover experimental unit cell volume.

post-dos, post-lopt

  • post-dos: Post-processing calculation from existing WAVECAR to determine the density of states, using NPAR = 1, LORBIT = 0, and RWIGS = 1.0 for all atoms.
  • post-lopt: Post-processing calculation from existing WAVECAR to determine the dielectric function in the independent particle approximation (LOPTICS = T, LPEAD = T).