"STM of Individual Dopants in Silicon towards Devices for Quantum Information Processing"

Abstract

The study of individual Group V donors in silicon is important due to their potential
application in spintronics and quantum computing. Recently a new programme has begun
with the aim of developing completely new, single dopant-derived devices in silicon
with functions based on principles from atomic physics – namely those of long-lived
quantum states and interactions between them and radiation fields.* If the project is
to be successful, the ability to position, characterise and manipulate individual
dopants in silicon must be established. I will describe our on-going efforts towards
these aims and show that it is possible to study individual Bi and Sb atoms in the
cleaved Si(111)2x1 surface, using a combination of ion implantation and cross-sectional
scanning tunnelling microscopy (XSTM). High resolution STM topography images and
scanning tunnelling spectroscopy (STS) data allow the experimental comparison of the
different structural and electronic properties of these individual group V donors, for
the first time. In addition, we have discovered an interesting strain effect in the
Si(111)2x1 surface that may provide a mechanism for controlling the local electronic
environment of individual dopants.

 

* Programme grant: COMPASSS - Coherent Optical and Microwave Physics for Atomic-Scale
Spintronics in Silicon