Professor and Department Chair
546 Reiss Science Building
Telephone: (202) 687-6583
Amy Liu received her A.B. in physics from Cornell University in 1985 and her Ph.D. in physics from U.C. Berkeley in 1991. After post-doctoral work at the Naval Research Laboratory and the NEC Research Laboratory, she joined the physics department at Georgetown.
Her primary research interests include the electronic, structural, and vibrational properties of crystals, interfaces, and clusters; electronic instabilities such as superconductivity and charge density waves; anharmonicity and thermal properties of materials.
Ab initio studies of materials
Computational quantum-mechanical approaches to the electronic structure of matter have proven to be useful tools for understanding and predicting the properties of materials. In recent work, we have used these tools to investigate
- electron-phonon coupling in layered superconductors, such as MgB2, intercalated graphite, and the hypothetical LiB. These materials share the common structural feature of graphene-like atomic layers, but calculations show that they take advantage of different mechanisms for achieving strong coupling between electrons and phonons.
- stability and bonding in boron cluster materials. Recently, large cage-like structures, analogous to the carbon fullerenes, have been predicted for boron clusters. We are interested in the stability of these boron clusters, both in the gas phase as well as in condensed forms
- competing instabilities in charge density wave materials. Charge density waves and superconductivity both result from electronic instabilities that lead to collective behavior of electrons in materials. We are studying materials where they coexist to better understand the relationship between these two phenomena: are they in competition, or do they cooperate with each other?
Assessment of student learning in physics
Most of the reform curricula and pedagogies for introductory physics developed by the Physics Education Research community were created and evaluated in the context of large-enrollment courses at public universities. We are assessing the effectiveness of some of these research-based reforms in courses for physics majors at Georgetown.
- R. R. Zope, T. Baruah, K. C. Lau, A. Y. Liu, M. R. Pederson, and B. I. Dunlap, Boron fullerenes: From B80 to hole doped boron sheets, Phys. Rev. B 79 161403(R) (2009)
- Y. Ge and A. Y. Liu, Effect of dimensionality and spin-orbit coupling on charge-density-wave transition in 2H-TaSe2, Phys. Rev. B 86 104101 (2012).
- Y. Ge and A. Y. Liu, Phonon-mediated superconductivity in electron-doped single-layer MoS2: A first-principles prediction, Phys. Rev. B 87, 241408(R) (2013).
- B. A. Lindsey and A. Y. Liu, Combining two reform curricula: An example from a course with well-prepared students, American Journal of Physics 81, 545 (2013).