Tuesday, November 17, 2015
4:00PM (334 JFB)
Title: Imaging and Spectroscopy of Individual Paramagnetic Electronic States on the Atomic Scale
Paramagnetic point defects such as the phosphorus donor in crystalline silicon are among the most coherent qubits found in nature. Using such systems for quantum applications will require detection and readout of single electrically isolated paramagnetic states with atomic scale spatial resolution that provides independent addressability of spin qubits.
The particular focus of the work presented here is the development of a single-spin magnetic resonance microscopy technique with atomic scale resolution based on spin-dependent single electron tunneling. A brief conceptual overview about single-spin magnetic resonance tunneling force microscopy is presented, which is expected to allow for the observation spin states of individual defects by random telegraph noise detection of spin-dependent tunneling into and out of a probe state. While this microscopy scheme has not been demonstrated yet, several milestones have been achieved for its implementation, including the demonstration that silicon dangling bonds (so called E' centers) have a suitable spin-dynamics for their utilization as spin-readout probes for the investigated spin-microscopy concept; that magnetic resonance based in-situ vector magnetometry in a low-temperature ultra-high vacuum scanning-probe setup is possible and that this can be used to establish well-controlled magnetic resonance conditions for the investigated samples; that the detection and imaging of individual phosphorous donor atoms, individual surface defect states, as well as charge currents that percolate through these states is possible under appropriate tip-to-sample bias conditions; and that random telegraph noise of the Coulomb forces caused by individual electrons that randomly tunnel into and out highly localized surface states can be observed.