CAREER: Novel Diamond Surface Functionalization and Nanoscale Surface Spectroscopy for Quantum Applications

Princeton University, Princeton NJ

Investigators

Abstract

Nontechnical description: Diamond crystals often contain imperfections, known as "color center defects", that are the size of a few atoms. These defects are known to be highly sensitive to the presence of single molecules in their vicinity, and may therefore be used to study the structure and function of molecules inside living cells. In order to accomplish this, color center defects must be placed very close to the molecules they will sense. This research project aims to construct a new instrument that enables completely new forms of probing and manipulating color center defects at the surface of diamond crystals. The development of small, sensitive sensors based this approach has the potential to impact diverse fields, ranging from ultrahigh-resolution biomedical imaging applications akin to MRI, to the discovery of new materials for future quantum computers. This research activity is integrated with advanced training for the next generation of scientists and engineers. The educational component of the project includes long-term research experience for undergraduates in partnership with Wellesley College, in which students participate in leading-edge research at Princeton University, with close mentorship during the academic year. Technical description: This project aims to gain control over the surface of diamond at the level of single atomic defects. Diamond hosts numerous isolated point defects that may be optically addressed. One such defect, the nitrogen vacancy (NV) center, exhibits excellent spin coherence at room temperature, allowing it to act as a highly sensitive magnetic sensor with sub-nanometer resolution. NV centers placed close to the surface can have strong interactions with other materials and molecules, but uncontrolled surface defects give rise to noise that obscures the signal of interest. This project develops new methods for controlling and spectroscopically probing the diamond surface. Central to this effort is the construction of an ultrahigh vacuum cluster tool to perform surface chemistry and traditional surface spectroscopy in tandem with quantum spectroscopy using single NV centers. The realization of shallow, coherent NV centers paves the way for numerous applications: imaging structure and dynamics of single proteins in ambient conditions, non-invasive sensors for materials characterization, and quantum information processing. This project provides advanced, interdisciplinary training to students and postdocs in optics, materials science, and quantum science. The research is also integrated with education, including a partnership between Princeton and Wellesley on a "20 Month REU" with research experiences at both institutions, and the development of a public demonstration on material properties of diamond, in collaboration with Element Six. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.