This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
A recent advance in Scanning Probe Microscopy has made it possible to image individual electron trap states in dielectric surfaces with atomic scale spatial resolution. In this method, a single electron is induced to tunnel between a scanning probe tip and an electronic state at the surface. Each individual electron tunneling event is detected by electrostatic force. This project aims to expand this exciting new capability to the detection and manipulation of single electron spins. A liquid helium temperature Single Spin Tunneling Force Microscope will be developed, capable of performing single spin Electron Spin Resonance (ESR) measurements and single spin manipulation. The instrument will consist of a low temperature Atomic Force Microscope, modified for force detection of spin-dependent single electron tunneling events with ESR excitation. The proposed instrument represents an entirely new approach to atomic scale single spin detection. It is based on the utilization of spin-selection rules, in contrast to previous approaches based on the detection of weak magnetic force detection. The instrument will enable chemical/physical identification (g-factor, energy, wavefunction imaging) of individual paramagnetic states, such as point defects found in dielectric and semiconductor materials, with atomic scale spatial resolution. It will also provide a means to study atomic scale magnetic fields and spin relaxation processes and will open a way to read out individual nuclear spins that are hyperfine coupled to adjacent electron spins. The project will train undergraduate and graduate students (emphasis on underrepresented groups) in state of the art atomic scale measurement techniques, and open up new collaborations with research groups within and outside the University of Utah.
Layman Summary: This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Spin is a fundamental property of electrons and some nuclei, which causes them to act like tiny bar magnets. Techniques allowing the observation of spins have had a profound impact in the past. The most prominent examples are based upon magnetic resonance, which is employed in medical diagnostics and analytical methods for chemistry and materials science. Most of these techniques detect many billions of spins. A few previous experiments conducted on very selective spin systems have demonstrated single spin detection. Most of these however could not resolve the spatial location of the spins very well, while others required extremely low temperatures. The proposed project aims to develop a new microscope which is able to detect individual electron spins with atomic scale precision over a range of temperatures. This instrument is called the Single Spin Tunneling Force Microscope. It is based on the quantum mechanical tunneling effect, a phenomena that allows electrons trapped in one region to traverse an impenetrable barrier and reappear on the other side. Tunneling of single electrons has already been observed with force microscopy. Tunneling can be influenced by electron spin. In the proposed instrument, spins are detected using the principle of spin dependent tunneling. The development of the proposed microscope could lead to dramatic progress in many research fields. The ability to observe individual spins in many materials and molecular systems could lead to breakthroughs for future spintronic devices. It could also significantly contribute to the development of quantum computers and help to understand atomic scale defects which influence conventional electronic materials and devices. The study of these defect spins can lead to insights into strategies for improvements in solar cells, semiconductor lighting devices, displays and computer applications.
