# Device package

One of the central elements of the `device`

package is the
`Device`

class, which can model a wide
range of real-world devices. In the first tutorial of this section, a silicon
nanowire gate-all-around field-effect transistor (GAAFET) is implemented
as a QTCAD
`Device`

object; the Schrödinger and Poisson equations are then
solved successsively in this system over a static mesh. In the second tutorial,
we explain how to use adaptive meshing for more robust solutions of the
non-linear Poisson equation at cryogenic temperature. In the third tutorial,
we explain how to account for user-defined parasistic background volume and
surface charge densities when solving the non-linear Poisson equation.
In the fourth tutorial, the Schrödinger equation is solved in a specific
region of a device after solving the non-linear Poisson equation with an
adaptive mesh.
In the fifth tutorial,
the Schrödinger equation is solved in a quantum dot. In the sixth tutorial,
the alignment of bands in heterostructures is explained. In the seventh
tutorial, the output of QTCAD simulations (e.g. electric potential and
wavefunctions) are visualized in ParaView. In the eighth tutorial, the
Schrödinger and Poisson equations are solved self-consistently for
a 1D metal–oxide–semiconductor capacitor. In the ninth tutorial,
we get the band structure for holes confined to a 1D particle-in-a-box-like
quantum well.
In the tenth tutorial, we look at the effects of spin–orbit coupling for
holes subject to a constant magnetic field.
In the eleventh tutorial, we demonstrate how strain can be used to modify the
character of the ground-state hole wavefunction.
In the twelfth tutorial, the eigenstates of an electron
confined in silicon are found using a multi-valley effective-mass theory.
In the thirteenth tutorial, the many-body problem is solved for the
GAAFET studied in the first tutorial.
In the fourteenth tutorial, a function is defined to produce
`Device`

objects for double quantum dots
defined in a generic fully-depleted silicon-on-insulator (FD-SOI) geometry.
We study tunnel coupling in such double-dot FD-SOI devices in tutorials fifteen
and sixteen of this section and exchange coupling in tutorials seventeen and
eighteen.
Finally, in tutorial nineteen, we investigate how point charges can affect the
quantum-dot energy spectrum in this same FD-SOI setting.

- 1. Poisson and Schrödinger simulation of a GAAFET
- 2. Poisson solver with adaptive meshing
- 3. Poisson solver with background charges
- 4. Adaptive-mesh Poisson solver combined with the Schrödinger solver
- 5. Schrödinger equation for a quantum dot
- 6. Band alignment in heterostructures
- 7. Visualizing QTCAD quantities with ParaView
- 8. Self-consistent Schrödinger–Poisson simulation of a MOS capacitor
- 9. Schrödinger simulation of a quantum well
- 10. Including spin–orbit coupling and magnetic effects in a simulation
- 11. Including strain in a simulation
- 12. Valley coupling (MVEMT)
- 13. Many-body analysis of a GAAFET
- 14. A double quantum dot device in a fully-depleted silicon-on-insulator transistor
- 15. Tunnel coupling in a double quantum dot in FD-SOI—Part 1: Plunger gate tuning
- 16. Tunnel coupling in a double quantum dot in FD-SOI—Part 2: Tuning the barrier gate
- 17. Exchange coupling in a double quantum dot in FD-SOI—Part 1: Perturbation theory
- 18. Exchange coupling in a double quantum dot in FD-SOI—Part 2: Exact diagonalization
- 19. Point charges in a double quantum dot in FD-SOI