9510518 von Molnar This interdisciplinary, two-campus project employs cutting-edge techniques from the fields of optical science and condensed matter physics. An ultra-high-vacuum scanning tunneling microscope will be used to synthesize both individual and arrays of magnetic structures directly on III-V semiconductor substrates and devices. The intrinsic magnetic behavior of the structures will be examined using microscopic Hall bar magnetometers, Aharonov-Bohm rings, ballistic transport, and high-sensitivity mechanical torque measurements. The influence of magnet particles on the spin-dependent electronic state in semiconductors will be investigated through femto-second-resolved Faraday and luminescence spectroscopes. In particular, the latter studies include spatially-resolved optical microscopy. %%% This experimental and theoretical project employs atomic-scale lithography, low-dimensional electronic transpopt, and ultra-fast magnetooptical spectroscopies at low temperature to investigate quantum magnetic structures. A unique aspect of the work is the in situ fabrication of "nanomagnets" only a few dozen atoms in diameter, whose optical and magnetic properties will be investigated. The work encompasses semiconductor physics, optics, and magnetism. The training gained by students in the areas of optical science and engineering will prepare them for a wide spectrum of career opportunities. The nanosize magnetic semiconductors exhibit novel magnetooptical phenomena that are currently incompletely understood, but which are felt to have great potential as possible device structures. ***
