Homepage of Xuan Gao

I am a postdoctoral associate at Prof. Charles Lieber's group at Harvard. I obtained my Ph.D. from Columbia University in 2003 and previously worked at Bell Labs, UC riverside and Los Alamos National Laboratory. Currently I am involved in the nanowire bio-sensor research at Lieber group. I am broadly interested in studying fundamental properties and biological application of semiconductor nanostructures (2D heterostructures, quantum wells, 1D quantum/nano-wires etc.). Download my CV.

Email me: xuan at cmliris.harvard.edu

Education

May 2003, Ph.D. in Applied Physics, Columbia University, Advisors: Prof. Aron Pinczuk (Columbia Univ.), Dr. Allen P. Mills Jr. and Dr. Art P. Ramirez (Bell Labs).

June 1998, B.S. in Applied Physics, South China University of Technology

Appointments

09/2005-now Postdoc at Professor Charles M. Lieber's group, Harvard University

09/2003-09/2005 Director's postdoctoral fellow, Los Alamos National Laboratory, Supervisors: Greg S. Boebinger and S. A. Crooker

01/2002-06/2003 Research staff, University of California, Riverside, Department of physics, Supervisor: Prof. Allen P. Mills Jr.

09/1999-12/2002 Graduate research associate, Bell Labs, Lucent Technologies, Supervisors: Art P. Ramirez and Allen P. Mills Jr.

09/1998-1999 Graduate teaching assistant, Columbia University

Honors and Awards

Director's postdoctoral fellowship, Los Alamos National Laboratory, Sep. 2003-Sep. 2005

The Robert Simon memorial prize for the most outstanding dissertation, Columbia University, Dept. of Applied Physics & Applied Mathematics, 2004

Honorable Mention, Mathematical Contest in Modeling, the U.S. consortium for Mathematics and its Applications, 1996, 1997

Research Interests and Expertise

Electronic properties (transport, thermodynamics) of electrons in low dimensional semiconductor quantum structures, with a focus on the interplay between impurities and interaction effects; Wigner crystallization, metal-insulator transition in two dimensions; non-Fermi liquid behavior in correlated electron systems; magnetic frustration; synthesis, functional engineering and fundamental study of semiconductor nanowire structures; interface between nano-science and biology; fundamental limits and application of biological/chemical sensing by nanowire bio-sensors.

Publications and Preprints

1) X. P. A. Gao, J. Y. Sohn, S. A. Crooker, "Low temperature terahertz spectroscopy of n-InSb through a magnetic field driven metal-insulator transition", Applied Physics Letter, 89, 122108 (2006); cond-mat/0605077.

2) X. P. A. Gao, G. S. Boebinger, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Spin polarization induced tenfold magneto-resistivity of highly metallic 2D holes in a narrow GaAs quantum well", Phys. Rev. B 73, 241315(R) (2006) (rapid communication); cond-mat/0506031.

3) M. Biasini, R.D. Gann, J.A. Yarmoff, A.P. Mills, L.N. Pfeiffer, K.W. West, X.P.A. Gao, and B.C.D. Williams, "Contactless gating, surface charging and illumination effects in a buried Al_0.24Ga_0.76As/GaAs quantum well structure", European Physical Journal B 47, 305 (2005).

4) M. Biasini, R.D. Gann, J.A. Yarmoff, A.P. Mills, L.N. Pfeiffer, K.W. West, X.P.A. Gao, and B.C.D. Williams, "Charging efficiency and lifetime of image-bound electrons on a dielectric surface", Appl. Phys. Lett. 86, 162111 (2005).

5) X. P. A. Gao, G. S. Boebinger, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Strongly Enhanced Hole-Phonon Coupling in the Metallic State of the Dilute Two-Dimensional Hole Gas", Phys. Rev. Lett. 94, 086402 (2005).

6) X. P. A. Gao, G. S. Boebinger, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Temperature and Magnetic Field Enhanced Hall Slope of a Dilute 2D Hole System in the Ballistic Regime", Phys. Rev. Lett. 93, 256402 (2004).

7) X. P. A. Gao, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Weak-localization-like temperature-dependent conductivity of a dilute two-dimensional hole gas in a parallel magnetic field", Phys. Rev. Lett. 89, 016801 (2002).

8) X. P. A. Gao, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Two-dimensional metal in a parallel magnetic field", Phys. Rev. Lett. 88, 166803 (2002).

9) I. S. Hagemann, Q. Huang, X. P. A. Gao, A. P. Ramirez, and R. J. Cava , "Geometric Magnetic Frustration in Ba₂Sn₂Ga₃ZnCr₇O₂₂:A Two-Dimensional Spinel Based Kagome Lattice", Phys. Rev. Lett. 86, 894 (2001).

10) P. Khalifah, K. D. Nelson, R. Jin, Z. Q. Mao, Y. Liu, Q. Huang, X. P. A. Gao, A. P. Ramirez, R. J. Cava, "Non-Fermi-liquid behavior in La₄Ru₆O₁₉", Nature411, 669 (2001).

11) X. P. A. Gao, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Insulator-Quantum Hall transition of dilute metallic 2D hole gas at high temperatures", submitted to Phys. Rev. B, rapid communications (2003); arXiv: cond-mat/0308003.

12) X. P. A. Gao, A. P. Mills, Jr., A. P. Ramirez, L. N. Pfeiffer, and K. W. West, "Joule heating of dilute 2D holes in a GaAs quantum well", arXiv: cond-mat/0203151 (2002).

13) A. P. Mills Jr., A. P. Ramirez, X. P. A. Gao, L. N. Pfeiffer, K. W. West, S. H. Simon, "Suppression of weak localization effects in low-density metallic 2D holes", submitted to Phys. Rev. Lett., arXiv: cond-mat/0101020 (2001).

Professional Societies

Member, American Physical Society

Professional Services

Referee for Physical Review Letters, Physical Review B, Nano Letters.

Invited Talks

Aug. 6^th, 2005, the fifth Physical Phenomena at High Magnetic Fields (PPHMF-V) conference, Tallahassee, Florida

Jul. 14^th, 2005, Purdue Univeristy

Jun. 3^rd, 2005, Harvard University, Chemistry Dept

Apr. 13^th, 2005, Stanford University

Apr. 11^th, 2005, University of California, Berkeley

Mar. 9^th, 2005, Texas Christian University

Feb. 24^th, 2005, The Ohio State University

Feb. 21^st, 2005, Clemson University

Feb. 17^th, 2005, University of Texas, Austin

Feb. 14^th, 2005, Tulane University

Jan. 7^th, 2005, " Fermi Liquid Interaction Induced Metallic Transport of Dilute 2D Holes in GaAs: A Critical Examination by the Hall Effect", workshop on the physics of ultra thin films near the metal insulator transition ( http://www.bnl.gov/thinfilms/ ), Brookhaven National Lab

May 17^th, 2004, " The metallic behavior and metal-insulator transition of dilute 2D holes in GaAs", Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey

Feb. 6^th, 2004, " The metallic state and metal-insulator transition in 2D: two decades of controversy", National High Magnetic Field Lab, LANL, Los Alamos

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