Su Ying Quek

Postdoctoral Fellow
Theory of Nanostructured Materials Facility, Molecular Foundry

2006 Ph.D., Applied Physics, Harvard University, USA
2001 Master of Science, Applied Mathematics, Harvard University, USA
2000 BA Honors (1st class), Mathematics, University of Cambridge, UK

Research Interests | Publications | Invited Presentations

I am currently working in the Theory Facility of the Molecular Foundry under the supervision of Jeffrey B. Neaton and Steven G. Louie. I am moving back to Singapore to take on a position as an Independent Investigator in the Institute of High Performance Computing (IHPC), with an adjunct faculty position in the Division of Physics and Applied Physics in Nanyang Technological University. I am looking for one or more qualified and enthusiastic postdoctoral researchers to work with me on computational electronic structure theory at IHPC. IHPC will be led by the Scientific Director Prof. David Srolovitz. As an Independent Investigator, my research will involve the development and application of first-principles techniques (DFT, excited-states, electronic transport, and beyond) for understanding and predicting properties of nanostructures at interfaces relevant to nanoscale electronics and spintronics, and energy conversion applications. Each postdoctoral researcher will work in my group for at least two years. He or she can start work anytime in 2011, with funding beginning as early as January 1st.

Research Interests

All matter is composed of electrons and nuclei. Knowing how these electrons and nuclei interact with one another is in principle sufficient to predict all physical and chemical properties of materials. In practice, treating these many-body interactions is often computationally intractable. However, by understanding the physical principles governing different approximations, we can make reasonably accurate estimates of many measurable quantities from first principles, with no adjustable parameters. I am interested in developing and applying first principles approaches to predict and control experimentally measurable quantities of materials, especially those at the nanoscale.

In recent years, I have focused on studying electron transport in single-molecule junctions. Predicting the electronic conductance through single-molecule junctions is an open problem. Most first principles calculations use density-functional theory which overestimates the conductance by an order of magnitude. Other approaches which incorporate many-electron effects are too expensive to model realistic systems. Using a density-functional-based approach with a physically motivated electron self-energy correction, my co-workers and I have obtained values of conductance that are in good agreement with experiment. Using this approach, we have been able to elucidate the nature of tunneling observed in experiment and provide guidance for experimental design. We have also used this same approach to predict the thermopower of single-molecule junctions, which is an independent but related probe of electronic transport at the Fermi level. Our computed results are in good agreement with experiment.

Complementary to the above approach, I am also interested in using the many-electron GW-Bethe-Salpeter approach to calculate quasiparticle and optical spectra. Besides providing information for direct comparison with experiment, the results can be used to understand and predict material properties, with applications to electronic charge and spin transport, for example.

During my graduate studies, I worked with Prof. Efthimios Kaxiras and Prof. Cynthia M. Friend on a variety of interesting surface science systems related to catalysis and electronic transport. I worked closely with experimentalists in the Friend group to predict and characterize the atomic structure and properties of novel oxides and sulfides on Au(111), and studied their implications for catalysis. I also worked with Prof. Steven G. Louie, Dr Jeffrey B. Neaton, and Dr. Mark S. Hybertsen, studying the level alignment of organic molecules on Si(100) using the GW approach, and predicting the conditions required for negative differential resistance in such systems.


  • M. Kamenetska, S.Y. Quek, A.C. Whalley, M.L. Steigerwald, H.J. Choi, S.G. Louie, C. Nuckolls, M.S. Hybertsen, J.B. Neaton, L. Venkataraman, "Conductance and Geometry of Pyridine-Linked Single Molecule Junctions", Journal of the American Chemical Society, in press
  • S.Y. Quek and E. Kaxiras, "Applications of Thin Film Oxides in Catalysis", Book Chapter in "Thin Film Metal-oxides: Fundamentals and Applications in Electronics and Energy", Edited by Ramanathan, Shriram, Springer (2010)
  • S.Y. Quek, H.J. Choi, S.G. Louie, and J.B. Neaton, "Length Dependence of Conductance in Aromatic Single-Molecule Junctions", Nano Letters, 9 (11), 3949-3953 (2009)
  • S.Y. Quek, M. Kamenetska, M.L. Steigerwald, H.J. Choi, S.G. Louie, M.S. Hybertsen, J. B. Neaton and L. Venkataraman, "Mechanically-Controlled Binary Conductance Switching of a Single-Molecule Junction", Nature Nanotechnology, 4, 230-234 (2009)
  • Y. Qi, I. Ratera, J.Y. Park, P.D. Ashby, S.Y. Quek, J.B. Neaton, M. Salmeron, "Mechanical and charge transport properties of alkanethiol self-assembled monolayers on Au(111) surface: The Role of Molecular Tilt", Langmuir, 24, 2219-2223 (2008)
  • X. Deng, S.Y. Quek, M.M. Biener, J. Biener, R. Schalek, E. Kaxiras and C.M. Friend, "Selective thermal reduction of single-layer MoO3 nanostructures on Au(111)", Surface Science, 602, 1166-1174 (2008)
  • S.Y. Quek, L. Venkataraman, H.J. Choi, S.G. Louie, M.S. Hybertsen and J.B. Neaton, "Amine-Gold Linked Single-Molecule Circuits: Experiment and Theory", Nano Letters 7, 3477-3482 (2007)
  • S.Y. Quek, M.M. Biener, J. Biener, J. Bhattacharjee, C.M. Friend, U.V. Waghmare and E. Kaxiras, "Structure of incommensurate gold sulfide monolayer on Au(111)", Journal of Chemical Physics 127, 104704-1-104704-8 (2007)
  • S.Y. Quek, J.B. Neaton, M.S. Hybertsen, E. Kaxiras and S.G. Louie, "Negative Differential Resistance in Transport through Organic Molecules on Silicon", Physical Review Letters 98, 066807 (2007)
  • S.Y. Quek, M.M. Biener, J. Biener, J. Bhattacharjee, C.M. Friend, U.V. Waghmare and E. Kaxiras, "Rich co-ordination chemistry of Au adatoms in gold sulfide monolayer on Au(111)", Journal of Physical Chemistry B 110(32), 15663-15665 (2006)
  • S.Y. Quek, J.B. Neaton, M.S. Hybertsen, E. Kaxiras and S.G. Louie, "First-principles studies of the electronic structure of cyclopentene monolayers on Si(001): Density functional theory and GW calculations", Physica Status Solidi (b) 243, 2048-2053 (2006)
  • S.Y. Quek, C.M. Friend and E. Kaxiras, "Active role of buried ultrathin oxide structures in catalysis: Au on reduced titania", Surface Science 600, 3388-3393 (2006)
  • S.Y. Quek, M.M. Biener, J. Biener, C.M. Friend and E. Kaxiras, "Tuning electronic properties of novel metal oxide nanocrystals using interface interactions: MoO3 monolayers on Au(111)", Surface Science Letters 577, L71-L77 (2005)

Invited Presentations

  • Invited Talk, Molecular Foundry User Meeting, November 2008. "First Principles Studies of Conductance and Mechanically-Controlled Switching in Single-Molecule Junctions"
  • Invited Talk, American Physical Society Meeting, New Orleans, Louisiana, March 2008. "Understanding the Conductance of Single-Molecule Junctions from First Principles"
  • Invited Talk, Molecular Conduction Workshop, Purdue University, July 2007. "Amine-Gold Linked Single-Molecule Junctions: First-Principles Calculations and Comparison to Experiment"
  • Invited Seminar, The Molecular Foundry, Lawrence Berkeley National Lab, September 2006. "First-Principles Studies of the Electronic Properties of Molecular Nanostructures and Novel Nanoscale Assemblies"
  • Invited Seminar, Nanyang Technological University, Singapore, August 2005. "Theoretical Investigations of Interfacial Effects in Nanoscale Structures"