Solid State Spectroscopy: Fundamental Physics and Device Applications

Our group investigates condensed matter systems using state-of-the-art spectroscopic techniques to probe charge, spin, and vibrational dynamics. Our experimental facilities include the RAMBO system — a unique mini-coil-based 30-T pulsed magnet system equipped with ultrafast and nononlinear optical spectroscopy setups. Some of our current interets include:

  • Optics and photonics of carbon nanotubes, graphene, and 2D materials
  • Physics and applications of terahertz phenomena
  • Spintronics, opto-spintronics, and optical quantum information processing
  • Nonlinear, ultrafast, and quantum optical phenomena in solids
  • Optical processes in ultrahigh magnetic fields

Results of our research will lead to an increased understanding of non-equilibrium many-body dynamics in condensed matter as well as development of novel opto-electronic devices.

Below are some recent highlights of our research. Please see the Publications page to see a full list of our publications.

Recent Research Highlights:

Y. Harada et al., “Giant Terahertz-Wave Absorption by Monolayer Graphene in a Total Internal Reflection Geometry,” ACS Photonics (2017) (abstract) N. Komatsu et al., “Modulation-Doped Multiple Quantum Wells of Aligned Single-Wall Carbon Nanotubes,” Advanced Functional Materials (2017). (abstract)
G. T. Noe II et al., “Single-Shot Terahertz Time-Domain Spectroscopy in Pulsed High Magnetic Fields,” Optics Express (2016) (abstract) Q. Zhang et al., “Stability of High-Density Two-Dimensional Excitons against a Mott Transition in High Magnetic Fields Probed by Coherent Terahertz Spectroscopy,” PRL (2016). (abstract)
Q. Zhang et al., “Collective non-perturbative coupling of 2D electrons with high-quality-factor terahertz cavity photons,” Nature Physics, (2016). (abstract) X. He et al., “Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes,” Nature Nanotechnology (2016). (abstract)
W. Gao et al., “Electroluminescence from GaAs/AlGaAs Heterostructures in Strong In-Plane Electric Fields: Evidence for k– and Real-Space Charge Transfer,” ACS Photonics, (2015).  (abstract)W.Gao ACS Photonics K. Cong et al., “Superfluorescence from Photoexcited Semiconductor Quantum Wells: Magnetic Field, Temperature, and Excitation Power Dependence,” Physical Review B 91, 235448 (2015).  (abstract, full text)cropped-kono-website-title.jpg
Q. Zhang et al., “Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases,” Physical Review Letters 113, 047601 (2014). (abstractfull textarXiv) X. He et al., “Carbon Nanotube Terahertz Detector,” Nano Letters 14, 3953 (2014). (abstractfull textRice News)
Q. Zhang et al., “Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes,” Nano Letters 13, 5991 (2013). (abstractfull textRice News)
J.-H. Kim, G. T. Noe II, et al., “Fermi-Edge Superfluorescence from a Quantum-Degenerate Electron-Hole Gas,” Scientific Reports 3, 3283 (2013). (abstractfull textRice News)
X. He et al., “Photothermoelectric p-n Junction Photodetector with Intrinsic Broadband Polarimetry Based on Macroscopic Carbon Nanotube Films,” ACS Nano 7, 7271 (2013). (abstractfull textRice News) S. Nanot et al., “Broadband, Polarization-Sensitive Photodetector Based on Optically-Thick Films of Macroscopically Long, Dense, and Aligned Carbon Nanotubes,” Scientific Reports 3, 1335 (2013). (abstractfull textRice News)
E. H. Hároz et al., “Fundamental Optical Processes in Armchair Carbon Nanotubes” (Feature Article), Nanoscale 5, 1411 (2013). (abstractfull textRice News) J.-H. Kim et al., “Coherent Phonons in Carbon Nanotubes and Graphene” (Invited Review Article), Chemical Physics 413, 55 (2013). (abstractfull text)

Single-Wall Carbon Nanotube (SWCNT) Assignment Table:

Sivarajan Chart for the electronic assignment of single-wall carbon nanotubes (SWCNTs). Most experimental data is for SWCNTs suspended in SDS. Each colored square represents a particular (n,m) species identified byn (left axis) and m (bottom axis).  The color (yellow, green, and blue) of each square indicates its respective electronic type (medium-gap semiconductor, small-gap semiconductor, and metal).  For each (n,m) species, the radial breathing mode (RBM) frequency (in cm^{−1})  and E_{11} resonance wavelength (in nm) are indicated. For semiconducting [(n − m) mod 3 = ±1] nanotubes, the E_{22} resonance wavelength (in nm) is also shown.  The red circle in the bottom left corner of some entries represents isoradial (n,m) pairs of identical diameters; the pairs are matched with the number “i” inside the red circle.  Values for E_{11} are taken from Ref. 1. Values for RBM frequency and E_{22} are taken Ref. 2.  Reproduced with permission, Copyright 2003, Ramesh Sivarajan. Updated by Erik H. Hároz on August 15, 2012.