• Atomic Physics
• Biophysics Theory and Experiment
• Cond Matter Experiment Faculty
  • Robert H. Austin
  • M. Zahid Hasan
  • Nai Phuan Ong
  • Jason Petta
  • Ali Yazdani
  • Sandra Troian (Chem Eng)
  • Daniel C. Tsui (Elec Eng)
  • Paul M. Chaikin (at NYU)

• Condensed Matter Theory
• Cosmology Experiment
• Cosmology Theory
• High Energy Experiment
• High Energy Theory
• Mathematical Physics
• Particle and Nuclear Astrophysics

• Quantitative and Computational Biology
• Cosmology at Princeton
• Lewis-Sigler Institute
• Princeton Center for Theoretical Physics
• Princeton Institute for the Science
  and Technology of Materials

My research interests are in the behavior of electrons in strongly-correlated materials, exemplified by the cuprates, cobaltates, manganites and ruthenates. Experiments over the past 2 decades have shown that charge transport in these systems is anomalous because of dominant electron-electron interaction. The key transport quantities resistivity, Hall effect and thermopower do not follow the usual textbook prescriptions based on simple metals. My group has been active in exploring experimentally the new patterns seen in these materials. A second interest is in the behavior of how charge transport is affected by spin ordering in all its guises (ferromagnetism, antiferromagnetism, spiral states). The research takes us far afield into diverse areas of condensed matter physics, ranging from superconductivity and magnetism to enhanced thermoelectricpower, spin currents and the Berry phase in ferromagnets. In our search for solids displaying interesting, unusual electronic behavior, we collaborate actively with Bob Cava's group in Chemistry to cast a wide net over the sea of transition-metal and rare-earth oxides. Research in N.P. Ong's Group

S e l e c t e d P u b l i c a t i o n s:

Z. Xu, N.P. Ong, Y. Wang, T. Kakeshita and S. Uchida, "Vortex-like excitations and the onset of superconducting phase fluctuation in underdoped La_2-x Sr_x CuO_4 ", Nature *406*, 486 (2000) Y. Zhang, N.P. Ong, P. W. Anderson, D. A. Bonn, R. X. Liang, and W. N. Hardy, Giant enhancement of the thermal Hall conductivity in high-purity YBa_2 Cu_3 O_7 ., Phys. Rev. Lett., *86*, 890 (2001). Yayu Wang, N. P. Ong, Z.A. Xu, T. Kakeshita, S. Uchida, D. A. Bonn, R. Liang and W. N. Hardy, High field phase diagram of cuprates derived from the Nernst effect, Phys. Rev. Lett. *88*, 257003 (2002) (cond-mat/0205299). Y. Zhang, R. H. Austin, J. Kraeft, E. C. Cox, and N. P. Ong, Insulating behavior of l -DNA on the micron scale., Phys. Rev. Lett., Phys. Rev. Lett. *89*, 198102 (2002). (physics/0205016). Yayu Wang, S. Ono, Y. Onose, G. Gu, Yoichi Ando, Y. Tokura, S. Uchida, and N. P. Ong, Dependence of upper critical field and pairing strength on doping in cuprates. Science, *299*, 86 (2003)/./ Yayu Wang, Nyrissa S. Rogado*, *R. J. Cava, and N. P. Ong*, *Spin entropy as the likely source of enhanced thermopower in Na_x Co_2 O_4 . Nature *423*, 425 (2003). Wei-Li Lee, Satoshi Watauchi, R. J. Cava and N. P. Ong, Dissipationless anomalous Hall current in the ferromagnetic spinel CuCr_2 Se_4-x Br_x . Science *303*, 1647 (2004).