Development of an Ultralow Temperature Scanning Probe Microscopy System for Magnetic and Electrostatic Imaging

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9975611Van HarlingenThis grant will provide partial support for the development of an advanced system to experiments that address key scientific issues in the study of unconventional superconductors, mesoscopic structures, and the two-dimensional electron gas. The invention and rapid advance of scanning probe microscopies (SPM) is a recent example of technology driving science. These innovative tools are changing our perception of the structure and properties of matter on nanometer scales. Imaging at very small-length scales is now possible for all kinds of materials, from semiconductors to biological samples to self-assembled devices. As a result, these microscopes are becoming essential tools to scientific research and technological development in diverse disciplines - condensed matter physics, advanced memory devices, and biology. The new system will extend the use of scanning probe microscopy for magnetic and electrostatic imaging to ultralow temperatures and high magnetic fields for the study of fundamental phenomena in condensed matter systems.The developed system will integrate some of the most advanced methods of SPM for measuring local magnetic and electric fields with a versatile top loading dilution refrigerator. In particular, scanning SQUID (Superconducting Quantum Interference Device), scanning Hall, and scanning capacitance microscopy techniques at ultralow temperatures will be implemented to achieve magnetic and electrostatic imaging on the microscopic scale. These techniques will allow mapping of electrostatic and magnetic fields on length scales of 10-100 nanometers at temperatures down to 20 millikelvin and fields up to 10 Tesla. This program will be a collaborative effort between two groups at UIUC with expertise in scanning probe microscopy and shared interest and current NSF support in studying fundamental phenomena in superconductors and mesoscopic structures at low temperatures.The experiments performed with this instrumentation will elucidate the nature of a wide range of low temperature phenomena and provide opportunities for new and exciting discoveries. The initial research plan includes experiments unraveling the nature of quantum phase transitions in two-dimensional superconductors, probing the structures of vortex lattices in unconventional superconductors, and search for secondary superconducting phases in mesoscopic structures resulting from the fragility of the order parameter in unconventional superconducting materials.This program will also impact the ongoing educational plans for the training of students in scanning probe microscopy and nanoscale imaging. These techniques are beginning to impact industrial development in the areas of data storage and future device technology, which remains the largest employers of condensed matter physicists in the industrial sector.%%%This equipment will enable the investigators to undertake very fundamental studies on new classes of materials, and to train studies in a very needy area.***