- Professor of Physics and Applied Physics
Professor Hoffman is interested in how electrons behave within quantum materials. Her research team at Harvard has two molecular beam epitaxy (MBE) systems and four low-temperature scanning probe microscopes to synthesize, visualize, and manipulate novel electronic states. Techniques include quasiparticle interference imaging to extract the band structure 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.
Superconductors – lossless electrical conductors – have potential for widespread application, but so far they function only at impractically low temperatures. The Hoffman lab is using MBE coupled with scanning tunneling microscopy (STM) to search for emergent high-Tc superconductivity at material interfaces. Furthermore, motion of vortices – quanta of magnetic flux – causes noise and dissipation in superconducting devices. Vortices can be pinned by the controlled introduction of defects 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. The combination of MBE-STM-MFM allows a closed feedback loop to improve material synthesis.
Topological insulators are 3D insulators with 2D metallic surface states. The robust spin-polarization of these surface states, and their protection against backscattering, suggests their utility for dissipationless spintronics 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 MBE for atomic-precision growth of novel heterostructures and STM to identify emergent behavior at the interfaces between topological and broken-symmetry materials.
Positions & Employment
- Professor, Harvard University, Physics Department, 3/2015-present
- Professor, University of British Columbia, Physics & Astronomy Department, 7/2015-6/2016
- Associate Professor, Harvard University, Physics Department, 7/2010-2/2015
- Assistant Professor, Harvard University, Physics Department, 1/2005-6/2010
- Postdoctoral Fellow, Stanford University, Applied Physics Department, 9/2003-12/2004
- Canada Excellence Research Chair, 2015-2016
- Moore Foundation Experimental Investigator Award, 2014
- Radcliffe Fellowship, 2013
- Sloan Fellowship, 2010
- NSF CAREER Award, 2008
- Presidential Early Career Award for Scientists and Engineers, 2006
- Fannie & John Hertz Foundation Fellow, 2001-2003
- Berkeley Physics Department Fellow, 1999-2001
- Barry Goldwater Scholar, 1998-1999