Email: younglee@mit.edu Phone: (617) 253-7834 Office: Room 13-2153 Labs: Rooms 13-2123, 13-2135, and 13-2143 Related Links: Argonne National Laboratory Keywords: Neutron and Synchrotron X-ray Scattering, Thermodynamic Measurements, Single Crystal Growth, Correlated Electron Systems, High Temperature Superconductivity, Frustrated Spin Systems, Quantum Phase Transitions

Research Interests

Professor Lee's research involves studies of novel electronic and magnetic materials in single crystalline form. The goal is to understand the properties of correlated electron systems and quantum spin systems, with an eye toward discovering new materials or new physical phenomena. A major shortcoming in the present knowledge of solid state physics is the inability to describe the properties of systems composed of many quantum particles which strongly interact with each other. The delicate interplay between the constituents of these correlated electron systems (involving the magnetic, charge, orbital, and lattice degrees of freedom) leads to a variety of exotic phases, such as high-T_c superconductivity and colossal magneto-resistance.

Specific areas currently under investigation include:

1) The interplay between spin- and charge-density wave order with the superconductivity in the high-T_c cuprates.

2) Metal-insulator transitions and magnetic phases in novel transition-metal oxides.

3) Quantum phase transitions in geometrically frustrated spin systems.

To study these, his group employs both microscopic probes (neutron and synchrotron X-ray scattering) and macroscopic techniques (thermodynamic and transport measurements). The scattering techniques are uniquely powerful probes of the collective behavior, allowing for detailed studies of the many-body response function. In combination with crystal growth, they have a fairly exhaustive effort for discovering and understanding new states of matter in condensed matter physics.

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Biographical Sketch

Professor Lee joined the Department of Physics as an Assistant Professor in the fall of 2001, and in July 2006 he was named to the Mark Hyman Jr. Career Development Professorship. He received a B.A. (with High Honors) in Physics from Princeton University in 1993. He completed his Ph.D. degree at MIT in 2000. His doctoral thesis was entitled "Neutron Scattering Study of the Magnetism and Structural Phases of Superconducting La₂CuO_4+y." From 1999 to 2001, he was an NRC Postdoctoral Research Associate at the NIST Center for Neutron Research, studying the lattice dynamics and spin excitations of strongly correlated electron systems.

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Selected Publications

1. "Incommensurate Geometry of the Elastic Magnetic Peaks in Superconducting La_1.88Sr_0.12CuO₄," H. Kimura, H. Matsushita, K. Hirota, Y. Endoh, K. Yamada, G. Shirane, Y.S. Lee, M.A. Kastner, and R.J. Birgeneau, Phys. Rev. B 61, 14366 (2000).

2. "Neutron Scattering Study of Spin Density Wave Ordering in the Superconducting State of Excess-Oxygen-Doped La₂CuO_4+y," Y.S. Lee, R.J. Birgeneau, M.A. Kastner, Y. Endoh, S. Wakimoto, K. Yamada, R.W. Erwin, S.H. Lee, and G. Shirane, Phys. Rev. B 60, 3643 (1999).

3. "Ordering due to Quantum Fluctuations in Sr₂Cu₃O₄Cl₂," Y.J. Kim, R.J. Birgeneau, F.C. Chou, M. Greven, M.A. Kastner, Y.S. Lee, A. Aharony, O. Entin-Wohlman, I.Y. Korenblit, A.B. Harris, R.W. Erwin, and G. Shirane, Phys. Rev. Lett. 83, 852 (1999).

4. "Instantaneous Spin Correlations in La₂CuO₄," R.J. Birgeneau, M. Greven, M.A. Kastner, Y.S. Lee, B.O. Wells, Y. Endoh, K. Yamada, and G. Shirane, Phys. Rev. B 59, 13788 (1999).

5. "Neutron-scattering Study of Static Antiferromagnetic Correlations in La_2-xSr_xCu_1-yZn_yO₄," H. Kimura, K. Hirota, H. Matsushita, K. Yamada, Y. Endoh, S.H. Lee, C.F. Majkrzak, R.W. Erwin, G. Shirane, M. Greven, Y.S. Lee, M.A. Kastner, and R.J. Birgeneau, Phys. Rev. B 59, 6517 (1999).

6. "Spin Correlations in the Two-Dimensional Spin-5/2 Heisenberg Antiferromagnet Rb₂MnF₄," Y.S. Lee, M. Greven, B.O. Wells, R.J. Birgeneau, and G. Shirane, Eur. Phys. J. B 5, 15 (1998).

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