## SETE

### SETE: *Single Electron Tunneling Elements*

#### Overview

SETE incorporates the realistic semiconductor wafer profile and gating pattern of a two dimensional electron gas (2DEG) heterostructure based device, such as a quantum dot or quantum wire, and calculates, within effective mass density functional theory, the potential profile, eigenfunctions and other properties of the structure.

#### Applications

Semiconductor heterostructures are the basis of low temperature (< 4K) devices that have, in recent years, made possible the manipulation of single charges, the quantization of conductance by a constriction, the reorganization of the 2DEG in the presence of a quantizing, perpendicular magnetic field and the exploration of correlation effects in double quantum dots intended for use as building blocks of quantum computation. SETE is a spin density functional theory based simulation that incorporates realistic device features and calculates the properties of such semiconductor heterostructures. The uses of SETE include facilitation of device design by providing reliable potential and density profiles as a function of gating geometries, wafer characteristics and applied surface voltages. Theoretical research and interpretation of experimental data are advanced by calculations of spectra and wave functions for confined regions (quantum dots), computations of the capacitance matrix of the device elements, computation of compressible and incompressible regions associated with integer and non-integer filling in a magnetic field, behavior of potential fluctuations in response to disorder in the donor layer, to name a few examples. A new feature of SETE is the computation of an exact diagonalized solution for the interacting two-electron problem in an arbitrary confined geometry (single, double, triple dot, etc.). A version of SETE for semiconductor and carbon nanowires will be available in the near future.

#### Developer

M. Stopa, Harvard U.

#### Getting started

A manual for SETE is in the writing stages and will be available at http://www.cns.fas.harvard.edu.

#### Relevant research articles:

- Quantum dot self-consistent electronic structure and the Coulomb blockade, M. Stopa, Phys. Rev. B, 54, 13767-13783 (1996).
- Fluctuations in quantum dot charging energy and polarization, M. Stopa, Semiconductor Science and Technology, 13, A55-A58 (1998).
- Rectifying behavior in Coulomb blockades: charging rectifiers, M. Stopa, Phys. Rev. Lett. 88, 146802 (2002).

For information contact: Michael Stopa, Harvard CNS, stopa@deas.harvard.edu.