Scholarly Interest Report


 

RuiRui Du  Professor  Professor of Physics and Astronomy   email:rrd@rice.edu    Postdoctoral Research Fellow (1990) Princeton University
 Ph. D. Physics (1990) University of Illinois at UrbanaChampaign
 B.S. Physics (1982) Fudan University, China, China
  Primary Department  Department of Physics and Astronomy     Department Affiliations   Rice Quantum Institute  
Websites   Research Group
  Research Group
 
Research Areas   Experimental condensed matter, nanophysics  
RESEARCH STATEMENT   Dr. Du’s research area and scholarly interests have been on the physics of low dimensional electron systems, especially on the fractional quantum Hall effect. The research work focuses on fundamental understanding of quantum mechanical properties of electrons in low dimensional and nanoscale semiconductor structures and devices. Here is an outline of current research topics. 2D and 1D electron systems provide both a clean laboratory for manyparticle physics and a unique platform addressing emerging issues in spintronics and solidstate quantum information devices. Our recent research has been centered on these two themes and has been supported by DOE, NSF, and DARPA. The materials used are mainly GaAs/AlGaAs heterostructures and quantum wells, but also include Si and InGaAs depending on the physics involved.
1. ManyParticle Physics in Ultracold 2D Electron Systems Experiments in 2D electron system (2DES) can be turned by many “knobs”, and multitude manyparticle electronic phases and phase transitions can be studied: fractional charged quantum fluid, Wigner lattices, Luttinger liquid, Stripes and liquid crystallike phases, and Skyrmions, to name a few. Not unlike in AMO where BoseEinstein condensation was discovered in ultracold atoms, the frontier of 2DES physics is on ultracold electrons. In collaboration with Columbia (Prof. Horst Stormer), Princeton (Prof. Dan Tsui), Stanford (Prof. Doug Osheroff), and funded by DOE, we have been pursuing a major research project (submillikelvin demagnetization refrigerator for solid state research) for experiments on ultracold electrons in lowD semiconductors and nanostructures. One of the objectives is to searching for exotic manyparticle electronic states that obey nonAbelien statistics, but there are much more: cooling electrons to lower than few millikelvin becomes increasingly relevant to general issues of quantum decoherence and phase transitions in electronic systems including mesoscopic metals, quantum dots, and quantum magnets. With the capability to cool 2D electrons to lower temperature, we will develop two important tools for studying manyparticle states: tunneling into edge of the quantum fluid and NMR for nuclear spins in the host materials (which in turn reflect the spin states in the 2DES).
2. Novel DC Transport Phenomena and Effect in a AC Driven Quantum Well Electrical transport of a 2DES exposed to a high frequency (from GHz to THz) driving electromagnetic wave is directly relevant to emerging issues concerning spintronics and quantum information processing. Fundamentally new phenomena of magnetoresistance oscillation and zeroresistance/zeroconductance have been discovered in our lab during the recent years (Phys. Today, Search & Discovery April 2003). We will continue to explore this new effect and its physics. One ongoing project is to develop a scanning Hall probe microscopy for simultaneously imaging the electrical current pattern formation and measuring dc transport. If this is successful we will be able to study the domain states proposed by theories in this novel effect.
3. Spin and Magnetic Phenomena Spin and spininteraction effects are the fundamental properties in 2D electron and 2D hole systems in semiconductors. Controlling spin polarization via electrical gates or microwave excitations is part of the research effort in my group. We have studied some interesting phenomena in magnetic alloys, such as DyAs, and more recently InGaAs.
4. SiBased Nanoelectronics Supported by a DARPA grant (University of Illinois) “Wavefunction engineering of individual donors for Sibased quantum computers” we have been participating in a quantum information project. The goal of this project is to place individual phosphorous (P) donors into silicon with atomic precision, and to demonstrate electrical control over the coupling between them as a function of their spin states. Our group is responsible for quantum transport measurement of the Sinanostructures produced by this atomscale STM patterning technique. We have shown that an ultradense (about 3 orders of magnitude higher than usual 2DES in GaAs) P donor sheets can be formed using this technique, and transport shows a metallic conduction at low temperatures. Recently a nanosize AharanovBohm ring has been fabricated and verified by our magnetotransport. In summary, our research will continue to focus on the manyparticle physics in lower dimensional electron systems, one of the most important and challenging areas in condensed matter sciences.   Teaching Areas   Solid state physics, Nanoscience and nanotechnology  
Selected Publications   Articles   I. Knez, C. T. Rettner, S. S. P. Parkin, L.J. Du, R.R.Du, and G. Sullivan, "Observation of Edge Transport in the Disordered Regime of Topologically Insulating InAs/ GaSb Quantum Wells", Phys. Rev. Lett. 112, 026602 (2014)    K. Stone, R. R. Du, M. J. Manfra, L. N. Pfeiffer, and K. W. West, Millimeter wave transmission spectroscopy of gated twodimensional hole systems, Appl. Phys. Lett. 100, 192104 (2012)    Fanming Qu, Chi Zhang, RuiRui Du, Li Lu, Coexistence of Bulk and Surface Shubnikovde Hass Oscillations in Bi2Se3, Journal of Low Temperature Physics 170, 397 (2013)
   Ivan Knez, RuiRui Du, and Gerard Sullivan, Andreev Reflection of Helical Edge Modes in InAs/GaSb Quantum Spin Hall Insulator, Phys. Rev. Lett. 109, 186603 (2012)    Guangtong Liu, Chi Zhang, D. C. Tsui, Ivan Knez, Aaron Levine, R. R. Du, L. N. Pfeiffer, and K. W. West, Enhancement of the ν=5/2 Fractional Quantum Hall State in a Small InPlane Magnetic Field, Phys. Rev. Lett. 108, 196805 (2012)    Ivan Knez and RuiRui Du, invited review article, Frontiers of Physics, 2011 SpringerVerlag Berlin, "Quantum spin Hall effect in inverted InAs/GaSb quantum wells ."    Ivan Knez, RuiRui Du, and Gerard Sullivan, "Evidence for Helical Edge Modes in Inverted InAs/GaSb Quantum Wells." Phys. Rev. Lett. 107, 136603 (2011)    Yanhua Dai, Kristjan Stone, Ivan Knez, Chi Zhang, R. R. Du, Changli Yang, L. N. Pfeiffer, and K. W. West, "Response of the microwaveinduced cyclotron harmonic resistance spike to an inplane magnetic field ." Physical Review B 84, 241303 (2011)    Chi Zhang, T. Knuuttila, Yanhua Dai, R. R. Du, L. N. Pfeiffer, and K. W. West, ν = 5/2 Fractional Quantum Hall Effect at 10 T: Implications for the Pfaffian State, Phys. Rev. Lett. 104, 166801 (2010)
   Ivan Knez, R. R. Du, and Gerard Sullivan, "Finite Conductivity in Mesoscopic Hall Bars of Inverted InAs/GaSb Quantum Wells", Physics Review B 81, 201301R (2010).    Jian Zhang, R. R. Du, J. A. Simmons, and J. L. Reno, Resistance Minimum Observed at Landau Level Filling ν = 1/2 in UltraHigh Magnetic Field, Physics Review B 81, 041308R (2010).    Yanhua Dai, R. R. Du, L. N. Pfeiffer, and K. W. West, "Observation of a Cyclotron Harmonic Spike in MicrowaveInduced Resistances in Ultraclean GaAs/AlGaAs Quantum Wells" , Physics Review Letters 105, 246802 (2010).    C. L. Yang, R. R. Du, L. N. Pfeiffer, and K. W. West, Phys. Rev. B 74, 045315 (2006), "Influence of a Parallel Magnetic Fields on the MicrowavePhotoconductivity in a HighMobility 2D Electron System."    Jian Zhang, R. R. Du, J. A. Simmons, and J. L. Reno, Phys. Rev. B 81, 041308 (2010), "Resistance Minimum Observed at Landau Level Filling Factor 1/2 in Ultra High Magnetic Fields."    K. Stone, C. L. Yang, Z. Q. Yuan, R. R. Du, L. N. Pfeiffer and K. W. West, Phys. Rev. B 76 153306 (2007), "Photovoltaic oscillations due to edgemagnetoplasmon modes in a very highmobility twodimensional electron gas."    M. A. Zudov, R. R. Du, L. N. Pfeiffer, and K. W. West, Phys. Rev. Lett. 96, 236804 (2006), "Bichromatic Microwave Photoresistance of a TwoDimensional Electron System."    S. J. Robinson, J. S. Kline, H. J. Wheelwright, J. R. Tucker, C. L. Yang, R. R. Du, B. E. Volland, I. W. Rangelow, and T.C. Shen, Phys. Rev. B 74, 153311 (2006), "Electron transport in laterally confined phosphorus δ layers in silicon."    Yanhua Dai, Z. Q. Yuan, C. L. Yang, R. R. Du, M. J. Manfra, L. N. Pfeiffer, and K. W. West, Phys. Rev. B 80, 041310 (2009), "Magnetotransport in Zener Tunneling Regime in a HighMobility TwoDimensional Hole Gas."    Z. Q. Yuan, C. L. Yang, R. R. Du, L. N. Pfeiffer, and K. W. West, Phys. Rev. B 74, 075313 (2006), "Microwave Photoresistance of a HighMobility Electron Gas in a Triangular Antidot Lattice."    Z. Q. Yuan, R. R. Du, M. J. Manfra, L. N. Pfeiffer, and K. W. West , Appl. Phys. Lett. 94, 052103 (2009), "Landau Level Spectrum in a TwoDimensional Hole Gas in CDoped (100) GaAs/Al0.4Ga0.6As Square Quantum Well."    M. A. Zudov, R. R. Du, L. N. Pfeiffer, and K. W. West, "Bichromatic Photoresistance of a TwoDimensional Electron System,." Phys. Rev. Lett. 96, 236804 (2006)    Editor of books   "Proceedings of the 16th International Conference on Electronic Properties of TwoDimensional Systems (EP2DS16)." Physica E 34, 1716 92006)    Refereed conference papers   R. R. Du, M. A. Zudov, C. L. Yang, Z. Q. Yuan, L. N. Pfeiffer, and K. W. West, "Oscillatory and Vanishing Resistance States in Microwave Irradiated 2D Electron Systems." Invited, Proceedings of the 16th International Conference on High Magnetic Fields in Semiconductor Physics”, eds. Y.J. Wang, L. Engel, N. Bonesteel, World Scientific, Singapore, 2005  
Presentations   Conference Committee Member   "Publication Committee, SCES'07 Houston." SCES' 07 Houston, Houston. (July 2007)    "Chair, Int. Program Committee, 16th Int. Conf. on Electronic Properties of TwoDimensional Systems, Albuquerque, NM, USA, July 1015, 2005."    "Chair, Int. Workshop on Macroscopic Quantum Phenomena, Chinese Academy of Sciences, Beijing, 711 June 2005."    Invited Papers   2010 International Workshop on Quantum Matter, May 2010    Nonlinear Transported in Modulated TwoDimensional Electron Systems, invited Symposium, "NonEquilibrium Transport in Very High Landau Levels", 2010 APS March Meeting (Portland, Oregon).    "5/2 States in High ElectronDensity GaAs/AlGaAs Quantum Wells." 18th International Conference on High Magnetic Field in Semiconductors and Nanotechnolwgies, Sao Pedro, Brazil. (08/03/0808/08/08) With Chi Zhang, T. Knuuttila, Yuanhua Dai, L. N. Pfeiffer, and K. W. West    Invited Talks   "Creating Majorana Fermions on the Edge of InAs/GaSb Quantum Wells", MaxPlanckInstitute for SolidState Research in Stuttgart, Germany, June 2628, 2013.    "Creating Majorana Fermions on the Edge of InAs/GaSb", MIT Chez Pierre CM seminar April 22, 2013.    "Quantized Edge States in InAs/GaSb Bilayers", Microsoft StationQ Meeting, Santa Barbara, December 6, 2013    Symposium on Majorana Physics in Condensed Matter, Ettore Majorana Center, Erice, Italy, July 12 18, 2013.    Quantum Spin Hall effect in InAs/GaSb Quantum Wells, Department of Physics, Stanford University, February 23, 2012    Quantum Spin Hall effect in InAs/GaSb Quantum Wells, RuiRui Du, Invited talk, International Workshop on Majorana Fermions in Condensed Matter, Lorentz Center, Leiden University, July 2 to July 6, 2012    Helical Edge Modes in Inverted ElectronHole Bilayers, RuiRui Du, Ivan Knez, and Gerard Sullivan, Invited talk, 31th International Conference on the Physics of Semiconductors, Zurich, Switzerland, July 29 to August 3, 2012    Quantum Hall Physics: From High Magnetic Field to Zero Magnetic Field, Invited talk, Beijing University, June 1, 2012    "A New 2D Topological Insulator from Semiconductors,." Tsinghua University, Beijing. (August 29, 2011)    "Edge Modes and Topological Superconducting States in Inverted InAs/GaSb Quantum Wells,." THE HEBREW UNIVERSITY OF JERUSALEM, THE INSTITUTE FOR ADVANCED STUDIES, The First ChinaIsrael Meeting on STRONGLY CORRELATED ELECTRON MATTER, (November 19, 2011)    "Perfect Andreev Refection of Helical Edge Modes in Nb‐Contacted InAs/GaSb Quantum Wells,." International Workshop “Superconducting hybrids: from conventional to exotic”, Villard de Lans, France. (Sepember 10, 2011)    "Quantum Spi Hall Effect in InAs/GaSb Quantum Wells,." International Workshop "World of Hall", Peking University, Beijing, (June 22, 2011)    "Quantum Spin Hall Effect in InAs/GaSb Quantum Wells,." Institute of Technicial Physics, Chinese Academy of Sciences, Shanghai , (June 27, 2011)    "Quantum Spin Hall Effect in Inverted ElectronHole Bilayers,." Kavli Institute for Theoretical Physics, University of California, Santa Barbara, (December 12, 2011)    "Topological Insulators Made of Inverted ElectronHole Bilayers, ." Institute of Physics, chinese Academy of Sciences, Beijing. (October 17, 2011)    Institute of Physics, Chinese Academy of Sciences, Beijing, June 2010    Institute of Semiconductors, Chinese Academy of Sciences, Beijing 2010    School of Physics, Beijing University, June2010    University of Chicago Beijing Center Opening Workshop, September 2010    "Quantum Hall Topological Phase at 5/2 Landau Level Filling Factor." Internationa Workshop on Quantum Information, Shanghai , July 2009, (7/10/09)    "Quantum Spin Hall Effect in InAs/GaSb Quantum Wells ." International Workshop on Quantum Matter, Hangzhou, 10/1210/15, 2009, (10/12/09)    "Searching For Quantum Spin Hall Effect in InAs/GaSb Semiconductors." International Workshop on Topological Quantum Phases, (6/23/2009)    "Transport in Inverted InAs/GaSb Quantum Wells." Institute of Physics, Chinese Academy of Sciences, (10/15/09)    "Experimental Aspects of the Quantum Hall Topological Phases." Kavli Institute for Theoretical PhysicsBeijing, Beijing, China. (June 2008)    "Experiments on Quantum Hall Topological Phases, Kavli Institute for Theoretical Physics." Kavli Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing. (June 2007)    Seminar Speaker   "Experiments on Quantum Hall Topological Phases." University of Science and Technology, Fudan University, JiaoTong University, (2008)    Session Chair   "International Workshop on Quantum Matter." Hong Zhou, October 2009,    "International Workshop on Topological Quantum Phases." Hong Kong, June 2009,    "International workshop on Quantum Information ." Shanghai, July 2009,    "Fractional Quantum Hall Effect." 18th International Conference on High Magnetic Field in Semiconductors and Nanotechnology, Sao Pedro, Brazil. (08/03/0808/08/08)    "Session Chair, APS March Meeting 2007." Denver. (March 2007)    Workshops   "International Workshop on Quantum Structures." Institute of Physics, Chinese Academy of Sciences, Beijing, China. (June 2008)    "Workshop on Quantum Spin Hall Effect (QSPIN)." Kavli Institute for Theoretical Physics, University of California at Santa Barbara. (12/08/0812/19/08)    "Organizer and Chair, Beijing Workshop on Quantum Transport, Chineses Academy of Sciences." Beijing. (December 2006)  
Editorial Positions   Editor for Special Issue, PHYSICA E. Elsevier B.V. (2008  2008)
  Member of the Editorial Board, Science in China. Springer. (2012  2014)

Supervised Theses & Dissertations   Kris Stone, MS Edge Magnetoplasmon in HighMobility 2D Electron Systems. (2007) (Thesis or Dissertation Director)
  Yanhua Dai, MS in Physics and Astronomy Nonlinear Transport in HighMobility TwoDimensional Hole Systems. (2009) (Thesis or Dissertation Director)
  Bei Hu, MS Space Physics. (2009) (Committee Member)
  Chanjuan Sun, Ph. D MagnetoOptical Spectroscopy of Novel Ferromagnetic Materials. (2010) (Committee Member)
  Ivan Knez, MS in Physics Quantum Spin Hall Effect in InAs/GaSb Quantum Wells. (2010) (Thesis or Dissertation Director)
  Ivan Knez, MS Quantum Transport in InAs/GaAsb Quantum Wells. (2010) (Thesis or Dissertation Director)
  Kristjan Stone, Ph. D Millimeter Wave Transmission Spectroscopy of 2D Electron and Hole Systems . (2010) (Thesis or Dissertation Director)
  Chi Zhang, Ph. D Fractional Quantum Hall Effect at Landau Level Filling Factor 5/2. (2010) (Thesis or Dissertation Director)
  Kristjan Stone, Ph. D in Physics and Astronomy Microwave Transmission Line Spectroscopy in TwoDimensional Electron Systems. (2010) (Thesis or Dissertation Director)
  Chi Zhang, Ph. D in Applied Physics Quantum Phases in High Mobility 2D Electron and Hole Quantum Hall Systems. (2010) (Thesis or Dissertation Director)
  Yanhua Dai, Ph. D Physics and Astronomy. (2011) (Thesis or Dissertation Director)
  Eileen Meyer, Ph. D Physics and Astronomy. (2011) (Committee Member)
  Yanhua Dai, Ph. D Nonlinear Quantum Transport in TwoDimensional Electron Systems. (2011) (Thesis or Dissertation Director)
  Yanhua Dai, Ph. D in Physics and Astronomy Quantum Interference in HighMobility TwoDimensional Electron Systems. (2011) (Thesis or Dissertation Director)
  Liheng Zheng, MS Physics and Astrnomy. (2011) (Committee Member)
  Ivan Knez, Ph. D Physics and Astrnomy. (2012) (Thesis or Dissertation Director)
  Jason Ball, MS Physics and Astronmy. (2012) (Thesis or Dissertation Director)
  Eileen Meyer, Ph. D Physics and Astronomy. (2012) (Committee Member)
  Ivan Knez, Ph. D Novel Semiconductor/ Superconductor Structures . (2012) (Thesis or Dissertation Director)
  Jason Ball, MS Physics and Astronomy. (2013) (Thesis or Dissertation Director)
  Xiaowei He, Ph.D Quantum Hall Topological Phases . (2013) (Thesis or Dissertation Director)
  Jason Ball, MS Physics and Astronomy. (2013) (Thesis or Dissertation Director)
  Jie Zhang, MS Physics and Astronomy. (2014) (Thesis or Dissertation Director)
  Jie Zhang, MS Physics and Astronomy. (2014) (Thesis or Dissertation Director)
  Lingjie Du, Ph. D Physics and Astronomy. (2015) (Thesis or Dissertation Director)
  Lingjie Du, Ph.D Physics and Astronomy. (2015) (Thesis or Dissertation Director)
  Lingie Du, Ph. D Physics and Astronomy. (2016) (Committee Member)
  Eileen Meyer, Ph.D Physics and Astronomy. (Committee Member)
  Patrick Wheeler, MS Physics and Astronomy. (Committee Member)
  Chi Zhang, MS in Applied Physics 5/2 States in High Electron Density Quantum Wells. (Thesis or Dissertation Director)

Awards, Prizes, & Fellowships   Fellow of the American Physical Society, American Physical Society (2003)
  Outstanding Young Researcher Award, OCPA (1997)
  A. P. Sloan Fellow, A. P. Sloan Foundation (1996)

