Jenny Hoffman
Clowes Professor of Science
Profile
Outside professional activities
Profile
Professor Hoffman is interested in how electrons behave in materials. Her research team at Harvard designs and builds scanning probe microscopes to visualize and manipulate this behavior directly. Innovative techniques include quasiparticle interference imaging to extract the band structure (energy-vs-momentum relationship) of materials at the nanoscale, and force microscopy to trigger nanoscale electronic phase transitions. Materials of particular interest Include high temperature superconductors, topological insulators, and strongly correlated vanadates, all of which present deep physics questions as well as potential for novel applications
Superconductivity - the lossless conduction of electrical current – has the potential for widespread energy-saving applications, but significant challenges remain. First, all known superconducting materials work only at cryogenic temperatures or center-of-the-earth pressures. A better understanding of the electronic behavior in known superconductors is required to guide the search for more practical materials. The Hoffman lab uses scanning tunneling microscopy (STM) to visualize and understand electron energies and interactions in superconductors. Second, motion of vortices – quanta of magnetic flux – causes noise and dissipation in superconducting devices. Vortices can be pinned by the controlled introduction of impurities into the superconductor. The Hoffman lab uses magnetic force microscopy (MFM) to manipulate individual superconducting vortices and directly quantify their interaction and pinning forces in picoNewtons.
Topological insulators are 3D insulators with 2D metallic surface states. The spin-polarization of these surface states, and their protection against scattering, suggests their utility for dissipationless spintronic devices. Furthermore, predicted topological behavior in proximity to superconducting or magnetic materials has led to numerous proposals for fault-tolerant quantum computing, as well as magnetoelectric effects for low-power-consumption electronics. The Hoffman lab uses molecular beam epitaxy (MBE) to synthesize thin layers and interfaces between these materials, to realize emergent properties that can’t exist in a single monolithic material. The Hoffman lab microscopes are crucial to image and understand the new materials and provide feedback for improved synthesis.
Superconductivity - the lossless conduction of electrical current – has the potential for widespread energy-saving applications, but significant challenges remain. First, all known superconducting materials work only at cryogenic temperatures or center-of-the-earth pressures. A better understanding of the electronic behavior in known superconductors is required to guide the search for more practical materials. The Hoffman lab uses scanning tunneling microscopy (STM) to visualize and understand electron energies and interactions in superconductors. Second, motion of vortices – quanta of magnetic flux – causes noise and dissipation in superconducting devices. Vortices can be pinned by the controlled introduction of impurities into the superconductor. The Hoffman lab uses magnetic force microscopy (MFM) to manipulate individual superconducting vortices and directly quantify their interaction and pinning forces in picoNewtons.
Topological insulators are 3D insulators with 2D metallic surface states. The spin-polarization of these surface states, and their protection against scattering, suggests their utility for dissipationless spintronic devices. Furthermore, predicted topological behavior in proximity to superconducting or magnetic materials has led to numerous proposals for fault-tolerant quantum computing, as well as magnetoelectric effects for low-power-consumption electronics. The Hoffman lab uses molecular beam epitaxy (MBE) to synthesize thin layers and interfaces between these materials, to realize emergent properties that can’t exist in a single monolithic material. The Hoffman lab microscopes are crucial to image and understand the new materials and provide feedback for improved synthesis.
Contact
Email: jhoffman@g.harvard.edu
Assitant: Helen Abraha: helen_abraha@fas.harvard.edu
Additional Website: https://www.physics.harvard.edu/people/facpages/hoffman
Expertise
Physics
Outside professional activities
Outside Professional Activities
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Outside Professional Activities For Jenny Hoffman
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The Salata institute
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