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WRT NMRCUR: Difference between revisions

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to select the current response triggered by <math>B_x</math>. It will result in a contour plot showing the magnitude of the current density and a quiver plot with the projected current in the selected plane. The plane is selected as a fraction <math>x</math> of the lattice vector. Here, <code>x=0.5</code> along <math>\mathbf{a}</math>. For the other lattice vectors use <code>b=x</code> or <code>c=x</code>.
to select the current response triggered by <math>B_x</math>. It will result in a contour plot showing the magnitude of the current density and a quiver plot with the projected current in the selected plane. The plane is selected as a fraction <math>x</math> of the lattice vector. Here, <code>x=0.5</code> along <math>\mathbf{a}</math>. For the other lattice vectors use <code>b=x</code> or <code>c=x</code>.
{{NB|warning|For bulk calculations you must switch off the use of symmetry. In other words, set {{TAGO|ISYM|0|op=<=}} if there is more than a single k point at zero (the Γ point).}}
{{NB|warning|For bulk calculations you must switch off the use of symmetry. In other words, set {{TAGO|ISYM|0|op=<=}} if there is more than a single k point at zero (the Γ point).}}
{{NB|tip|Consider switching on current augmentation ({{TAGO| LLRAUG|True}}).}}
{{NB|tip|Consider switching on current augmentation ({{TAGO| LLRAUG|True}}).}}



Revision as of 11:38, 7 March 2025

WRT_NMRCUR = 0 | 1 | 2 | 3 | 4
Default: WRT_NMRCUR = 0 

Description: Allows to write the NMR current response in atomic units to file.


In conjunction with LCHIMAG = True, WRT_NMRCUR allows to write the current response on the fine grid NGXF x NGYF x NGZF in atomic units (hartree bohr[math]\displaystyle{ ^{-2} }[/math]) to an external magnetic field within linear response NMR. The output is written to NMRCURBX, NMRCURBY, and/or NMRCURBZ depending on the selected direction of the perturbing [math]\displaystyle{ \mathbf{B} }[/math] field:

  • WRT_NMRCUR = 0: no current response written to file (default)
  • WRT_NMRCUR = 1: [math]\displaystyle{ B_x }[/math]
  • WRT_NMRCUR = 2: [math]\displaystyle{ B_y }[/math]
  • WRT_NMRCUR = 3: [math]\displaystyle{ B_z }[/math]
  • WRT_NMRCUR = 4: all three directions of [math]\displaystyle{ \mathbf{B}=(B_x,B_y,B_z)^T }[/math]

It is also written to vaspout.h5, if compiled with HDF5 support. You can find the data groups

 /results/nmrcurbx        Group
 /results/nmrcurbx/grid   Dataset {3}
 /results/nmrcurbx/structure Group
 /results/nmrcurbx/structure/position Group
 /results/nmrcurbx/structure/position/direct_coordinates Dataset {SCALAR} 
 /results/nmrcurbx/structure/position/ion_sha256 Dataset {1}
 /results/nmrcurbx/structure/position/ion_types Dataset {1}
 /results/nmrcurbx/structure/position/lattice_vectors Dataset {3, 3}
 /results/nmrcurbx/structure/position/number_ion_types Dataset {1}
 /results/nmrcurbx/structure/position/position_ions Dataset {2, 3}
 /results/nmrcurbx/structure/position/scale Dataset {SCALAR}
 /results/nmrcurbx/structure/position/system Dataset {SCALAR}
 /results/nmrcurbx/values Dataset {3, 24, 24, 24}

and use py4vasp to access these, e.g., using

import py4vasp as pv
calc = pv.Calculation.from_path(".")
calc.current_density.plot("NMR(x)", a=0.5)

to select the current response triggered by [math]\displaystyle{ B_x }[/math]. It will result in a contour plot showing the magnitude of the current density and a quiver plot with the projected current in the selected plane. The plane is selected as a fraction [math]\displaystyle{ x }[/math] of the lattice vector. Here, x=0.5 along [math]\displaystyle{ \mathbf{a} }[/math]. For the other lattice vectors use b=x or c=x.

Related tags and articles

LCHIMAG, LLRAUG, NMRCURBX