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Fully relativistic pseudopotentials

Fully relativistic pseudopotentials generated by
the MBK (PRB 47, 6728 (1993)) scheme within LDA (CA13) and GGA (PBE13) which contain
a partial core correction and fully relativistic effects including spin-orbit coupling.

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Pseudo-atomic orbitals

The number below the symbol means a cutoff radius (a.u.) of the confinement
potential. These file includes fifteen radial parts for each angular
momentum quantum number l (=0,1,2,3). The basis functions were generated by variationally
optimizing the corresponding primitive basis functions in the single atom and the BCC bulk.
The input files used for the orbital optimization can be found at
K_opt.dat
and
Kbcc_opt.dat.
Since K_CA13.vps and K_PBE13.vps include the 3s, 3p, and 4s (9 electrons)
as the valence states, the minimal basis set is K*.*-s2p1.
Our recommendation for the choice of cutoff radius of basis functions is that
K10.0.pao is enough for bulks, but K12.0.pao or K14.0.pao is preferable
for molecular systems.

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Benchmark calculations by the PBE13 pseudopotential with the various basis functions

**(1) Calculation of the total energy as a function of lattice constant in the bcc structure,**
where the total energy is plotted relative to the minimum energy for each case. a_{0}
and B_{0} are the equilibrium lattice constant and bulk modulus obtained by fitting to
the Murnaghan equation of state. The difference between K10.0-s4p3d2 and K10.0-s4p3d3f1
in the total energy at the minimum point is 0.0029 eV/atom.
An input file used for the OpenMX calculations can be found at
Kbcc-EvsV.dat.
For comparison the result by the Wien2k code is also shown, where
the calculation was performed by default setting in the Ver. 9.1 of Wien2k except for
the use of R_{MT} x K_{MAX} of 12.

**(2) Calculations of the band dispersion in the bcc structure,**
where the non-spin polarized collinear calculation with the lattice constant of 5.225 Ang.
was performed using K_PBE13.vps and K10.0-s4p3d2,
and the origin of the energy is taken to be the Fermi level.
The input file used for the OpenMX calculations can be found at
Kbcc-Band.dat.
For comparison the result by the Wien2k code is also shown, where
the calculation was performed by default setting in the Ver. 9.1 of Wien2k
except for the use of R_{MT} x K_{MAX} of 12.