Research Group Content

Research Activities

Spin dependent processes in semiconductors

 
We investigate fundamental spin dependent processes in semiconductors to provide a strong basis for the remainder of our research. We use phosphorus doped silicon (Si:P) as a model system, as its electrical properties are well understood(see, eg: McCamey et al., Phys. Rev. B (2008)). Due to the ubiquity of silicon in the modern semiconductor industry, we are able to exploit the vast processing expertise which this has generated.
 

Spins in Organic Electronics

 
 
Organic electronics are an increasingly important class of consumer electronics. However, understan
ding spin properties in organic materials remains difficult. We have shown that coherent manipulation of spins in organic electronic devices leads to changes in recombination and dissociation rates, and ultimately to changes in device conductivity. This has allowed us to access spin physics in these materials, where we have shown that phase cohrence times in some organic material is longer than 0.5 microseconds(see, eg: McCamey et al., Nature Materials (2008)). This has implication for a range of physical phenomena such as magnetoresistance in this material, and may also allow the development of more efficient organic optoelectronic devices.

 

Ultrasensitive spin detection

 
We are working towards electrical detection of the spin of a single donor atom in silicon (see, eg: McCamey et al., Appl. Phys. Lett. (2006)). This work is motivated by proposals for quantum information processing using the nuclear or electronic spins of phosphorus donors in silicon (eg: Kane, Nature 393, 133 (1998)). To detect very small numbers of donors, we use nanoelectronic devices fabricated with electron beam lithography and ion-implantation, measured at cryogenic temperatures.
 

Coherent spin effects in high magnetic fields

 
In collaboration with the National High Magnetic Field Laboratory and the University of Utah, we have electrically detected coherent spin manipulation at the highest magnetic fields reported to date (B = 8.5 T) (see Morley et al., Phys. Rev. Lett. (2008)). This technological advance has resulted in the ability to measure the longest electrically detected spin lifetime in a solid-state system (in this case silicon), which is of great importance to possible quantum electronics applications with silicon.
We have also recently shown that electron spin information can be transferred to and stored in the nuclear spin of donor atoms for over 100 seconds, and read out electrically via the hyperfine interaction (see McCamey et al., Science (2010)). This proof-of-principle demonstration opens the door to high density nuclear spin memories, as well as possible readout mechanisms for nuclear spin base quantum information processing.
For more information, see "No Matter How You Spin It" in Scientific American, "Semiconductor memory stores spins" at at physicsworld.com or listen to "Spintronics: A New Way To Store Digital Data" on NPR.