User Tools
nnp:transmission:transmission_through_a_3d_nanowire
Differences
This shows you the differences between two versions of the page.
| Next revision | Previous revision | ||
|
nnp:transmission:transmission_through_a_3d_nanowire [2019/10/18 13:29] takuma.sato created |
— (current) | ||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | ===== Transmission through a 3D nanowire ===== | ||
| - | We apply the Contact Block Reduction (CBR) method to a simple GaAs nanowire of cuboidal shape. | ||
| - | The corresponding tutorial for nextnano<sup>3</sup> is [[https://www.nextnano.com/nextnano3/tutorial/3Dtutorial_CBR_nanowire.htm|here]]. To simulate 3D (or 2D) system with CBR method in nextnano++ correctly, The quantum regions have to be appropriately specified in the input file. | ||
| - | <code> | ||
| - | quantum{ | ||
| - | region{ | ||
| - | name = "lead_1" | ||
| - | x = [-5,5] | ||
| - | y = [-5,5] | ||
| - | z = [-0.1,0.1] | ||
| - | boundary{ x=dirichlet y=dirichlet z=cbr } | ||
| - | Gamma{ num_ev = $num_eigenstates_device } | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | Since the simulation is three dimensional, the lead region specified here has to be two dimensional. The number $\pm0.1$ is chosen to be smaller than the grid spacing, so that the region "lead_1" becomes a 2D sheet (//Note: this is slightly different in nextnano<sup>3</sup> input//). CBR boundary condition has to be imposed in the propagation direction, i.e. z-direction, whereas Dirichlet boundary condition is set for perpendicular directions. | ||
| - | <code> | ||
| - | cbr{ | ||
| - | name = "device" | ||
| - | lead{ name = "lead_1" } | ||
| - | lead{ name = "lead_2" } | ||
| - | delta_energy = $delta_energy | ||
| - | abs_min_energy = $E_min | ||
| - | abs_max_energy = $E_max | ||
| - | options = [1, 0, 0] | ||
| - | } | ||
| - | </code> | ||
| - | The program calculates transmission through the region "device". On this device, two leads are attached. The resolution, minimum and maximum of the energy axis can be also tuned here. | ||
nnp/transmission/transmission_through_a_3d_nanowire.1571405394.txt.gz ยท Last modified: 2019/10/18 13:29 by takuma.sato
