Spinors with Quantum Espresso
Note that c2x 2.41 or later is required for this example.
This example closely follows the Mn3Sn Castep example, with just the differences highlighted.
Note that QE describes the initial spins in terms of spherical co-ordinates r,θ,φ whereas Castep uses Cartesians x,y,z. Also QE regards atoms with different initials spins as being different species, albeit sharing pseudopotentials. C2x can convert between the .cell and .in formats.
I am generally confused by the wide choice of QE pseudopotentials. The ones below seem to work, although they may not be optimal for this problem.
$ curl -o Mn.UPF http://pseudopotentials.quantum-espresso.org/upf_files/Mn.rel-pbe-spn-kjpaw_psl.0.3.1.UPF $ curl -o Sn.UPF http://pseudopotentials.quantum-espresso.org/upf_files/Sn.rel-pbe-dn-kjpaw_psl.1.0.0.UPF
QE may then be run as usual.
$ pw.x -n Mn3Sn.in > Mn3Sn.log &
It will take around a core-hour. Unlike Castep, QE will use symmetry for this calculation.
It reports total magnetisation
total magnetization = -0.01 0.00 -0.00 Bohr mag/cell absolute magnetization = 19.30 Bohr mag/cell
and also magnetisation per atom after some form of population analysis in a block containing text such as
atom number 3 relative position : 0.4920 0.5727 0.1997 charge : 13.692039 magnetization : 3.038704 0.001398 -0.000000 magnetization/charge: 0.221932 0.000102 -0.000000 polar coord.: r, theta, phi [deg] : 3.038704 90.000000 0.026358
pwscf.save/charge-density are present, then one can
run c2x as
$ c2x -sv --vec2force=Mn:1.37i pwscf.xml Mn3Sn.xsf
Data contain 3 components. Per component analysis: min=-2.70618 max=5.41896 sum=-6.61295 int=-0.011441 int|s|=12.8391 min=-4.63401 max=4.69038 sum=1.60634 int=0.00277911 int|s|=11.4669 min=-0.00648757 max=0.00648757 sum=-3.6533e-17 int=-6.32051e-20 int|s|=0.0223973 with s as vector, min(|s|)=0.000040, max(|s|)=5.418967, int|s|=19.302143 (integral is e per cell for charge and spin densities) Sampling of vector data integrating over 1.370000A using 22 points radially Mn at (0.8227,0.6613,0.2500) vector ( 3.1000, 0.0014,-0.0000) modulus 3.1000 Mn at (0.3387,0.6613,0.2500) vector (-1.5544,-2.6815, 0.0000) modulus 3.0994 Mn at (0.3387,0.1773,0.2500) vector (-1.5515, 2.6814, 0.0000) modulus 3.0979 Mn at (0.6613,0.8227,0.7500) vector (-1.5514, 2.6813, 0.0000) modulus 3.0978 Mn at (0.6613,0.3387,0.7500) vector (-1.5544,-2.6816, 0.0000) modulus 3.0996 Mn at (0.1773,0.3387,0.7500) vector ( 3.1001, 0.0014, 0.0000) modulus 3.1001
The total magnetisation of (-0.01, 0.00, 0.00) reported by QE corresponds to the integrals of (-0.011, 0.003, -6e-20) reported by c2x. The absolute magnetisation of 19.30 Bohr/cell corresponds to the c2x report of 19.302.
Above is show the resulting XSF file viewed in Vesta.