New knowledge about "flawed" diamonds could speed the development of diamond-based quantum computers
12 Oct 2011
![]() |
UB researcher Peihong Zhang and colleagues have established the presence of a dynamic effect in defective diamonds, a finding that will help advance the development of diamond-based quantum information processing. |
The research was published online 30 September in Physical Review Letters.
The findings deal with diamonds whose crystal structure contains a particular defect: a nitrogen atom that sits alongside a vacant space in an otherwise perfect lattice made only of carbon.
At the point of the imperfection - the so-called "nitrogen-vacancy center" - a single electron can jump between different energy states. (The electron rises to a higher, "excited" energy state when it absorbs a photon and falls back to a lower energy state when it emits a photon).
Understanding how the diamond system behaves when the electron rises to an excited state called a "3E" state is critical to the success of such proposed applications as quantum computing.
The problem is that at the nitrogen-vacancy center, the 3E state has two orbital components with exactly the same energy - a configuration that is inherently unstable.
In response, the lattice "stabilises" by rearranging itself. Atoms near the nitrogen-vacancy center move slightly, resulting in a new geometry that has a lower energy and is more stable.
This morphing is known as the Jahn-Teller effect, and until recently, the effect's precise parameters in defective diamonds remained unknown.
![]() |
Calculated energy surface of the 3E excited state of a diamond nitrogen-vacancy center as a function of distortions, a shape that is often referred to as a "warped Mexican hat." |
Their findings align with experimental results from other research studies, and shed light on important topics such as how long an excited electron at the nitrogen-vacancy center will stay coherently at a higher energy state.
The UB-Rensselaer study was funded by the Department of Energy.
The University at Buffalo is a premier research-intensive public university, a flagship institution in the State University of New York system and its largest and most comprehensive campus.