nextnano.com
 GUI: nextnanomat
 Tool: nextnano++
 Tool: nextnano³
 Tool: nextnano.QCL

 Download | SearchCopyright | News | Publications
 * password protected

 

nextnano³ software

 

  Magnetic-field

 

 

 
Up
 

Magnetic field

One can apply a magnetic field for 2D and 3D simulations. Note that the magnetic field is only implemented for single-band effective mass but not for k.p.
(For the combination of k.p and magnetic field, please use the nextnano++ software.)

  • 1D: magnetic field not possible
  • 2D: magnetic-field-direction must be perpendicular to simulation orientation.

    E.g.
    if

      !---------------------------------------!
      $simulation-dimension                   !
       dimension                = 2           !
       orientation              = 0 1 1       ! simulation in (y,z) plane
      $end_simulation-dimension               !
      !---------------------------------------!

     
    Then magnetic-field-direction must be
       magnetic-field-direction = 1 0 0
  • 3D: magnetic-field-direction can have any direction. The vector B must be specified with respect to the xyz simulation system, i.e. you cannot specify the four-digit Miller-Bravais indices as in the case for wurtzite. It is with respect to the x, y and z coordinate axes that were specified under $domain-coordinates:
    (If not specified, default values specified in database_nn3.in are taken.)

     x y z  :=  hkl-x-direction-zb, hkl-y-direction-zb, hkl-z-direction-zb
     
    or
     x y z  :=  hkil-x-direction,   hkil-y-direction,   hkil-z-direction

 

!--------------------------------------------------------------!
$magnetic-field                                       optional !
 magnetic-field-on                     character      required !
 magnetic-field-strength               double         required !
 magnetic-field-direction              integer_array  required !
                                                               !
 magnetic-field-sweep-active           character      optional !
(optional, only needed for magnetic field sweep)
 magnetic-field-sweep-step-size        double         optional !
(optional, only needed for magnetic field sweep)
 magnetic-field-sweep-number-of-steps  integer        optional ! (optional, only needed for magnetic field sweep)
$end_magnetic-field                                   optional !
!--------------------------------------------------------------!

 

Syntax

!--------------------------------------------------------------!
$magnetic-field                                                !
 magnetic-field-on                    = yes                    ! yes/no
 magnetic-field-strength              = 4.0d0                  ! [T]
(T=Tesla)
 magnetic-field-direction             = 1 0 0                  !
                                                               !
 magnetic-field-sweep-active          = yes                    ! yes/no

 magnetic-field-sweep-step-size       = 0.5d0                  ! [T] (T=Tesla)
 magnetic-field-sweep-number-of-steps = 10                     !  number of magnetic field sweep steps
$end_magnetic-field                                            !
!--------------------------------------------------------------!
 

magnetic-field-strength refers to the magnetic flux density B which has the following SI unit: 1 T = 1 Vs / m²

Note that the SI unit for the magnetic field strength H is [A/m].

 

Magnetic field sweep

It is possible to sweep over the magnetic field strength, i.e. to vary the strength of the magnetic field stepwise. This is similar to electric field sweeps ($electric-field), voltage sweeps ($voltage-sweep) and doping concentration sweeps ($doping-function).
The output is labeled with _ind000.dat, _ind001.dat, _ind002.dat, ... where the index refers to the number of the magnetic field sweep step.

The output for the eigenvalues as a function of applied magnetic field can be found here:
   magnetic_ev2D_vb001_qc001_sg001_deg001_dir_Kx001_Ky001_Kz001.dat.
In this particular example, the heavy hole valence band edge energies ('vb001') that have been obtained with the two-dimensional ('2D') single-band ('sg') Schrödinger equation with Dirichlet ('dir') boundary conditions have been written out as a function of magnetic field.
The first column contains the strength of the magnetic field in units of [T].
The second column contains the 1st  eigenvalue for the specified electric field in units of [eV],
the third      column contains the 2nd eigenvalue for the specified electric field in units of [eV], ...