Experimental Research

Top ⇑Materials Engineering

Principal Investigator: Douglas Chrisey

Tulane Group Members: Shiva Adireddy, Venkata Puli, Sijun Luo, Josh Shipman, Charlie Sklare, Theresa Phamduy and Brian Riggs

Group Website

Our research interests are wide ranging and include the novel laser fabrication of thin films and coatings of advanced materials for electronics, sensors, biomaterials, and for energy storage. The new materials were used in device configurations for testing and typically had an improved figure-of-merit. He is considered one of the pioneers in the field of Pulsed Laser Deposition and was the lead inventor of MAPLE processing technique (matrix assisted pulsed laser evaporation). He is currently publishing in areas of metallic nanoparticle fabrication, biosensing, bionanotechnology, tissue engineering, stem cell processing, ceramics, and polyamorphism.

Top ⇑Experimental Solid State Physics

Principal Investigator: David L. Ederer (Emeritus)

Tulane Group Members: Tim Schuler

Professor David L. Ederer was a senior staff scientist in the Center for Atomic, Molecular and Optical Physics at the National Institute of Standards and Technology (NIST), for almost thirty years. He came to Tulane in January 1992 to launch a new program in experimental solid state physics with the Center for Advanced Microstructures and Devices (CAMD) in Baton Rouge, as a focal point. Ederer carries out research on transition metals and rare earth materials at the Advanced Light Source as well, using soft x-rays to elucidate the electronic properties of complex and highly correlated materials such as high Tc superconductors. Ederer, a fellow of the American Physical Society, is an internationally recognized expert in the use of synchrotron radiation for research in atomic, molecular, and solid state physics. His research in atomic, and condensed matter physics, as well as instrument design has resulted in over one hundred and fifty papers.

Recent topics of research have included doped manganate systems, the superconducting perovskite Sr2RuO4 system and multi-layered variants, and magnetically doped semiconductors with particular focus on half-metallic behaviour.

Top ⇑Photonic Materials & Devices

Principal Investigator: Matthew Escarra

Tulane Group Members: Brian Riggs, Adam Ollanik, John Robertson, Vera Ji, Kazi Islam, Max Woody, Briley Bourgeois, Jacqueline Failla, David Bar-Or, and Claire Davis

Group Website

The Escarra group explores novel photonic materials and devices with applications particularly, but not exclusively, in the area of solar energy conversion. On the fundamental end, we are exploring nanoscale photonic materials and devices, where quantum phenomena tend to dominate, for potential use as light emitters, photovoltaics, and more. We are also interested in nanostructured materials, where sub-wavelength, or nanophotonic, behavior determines optical properties. On the applied end, we are developing unique material, device, and system architectures for ultra-high efficiency solar energy conversion. 

Active project thrusts include:

1)    In collaboration with academic and industry partners, the group is developing a new hybrid solar energy converter that allows for high efficiency, dispatchable renewable energy production. This system features a spectrum splitting photovoltaic module designed to work in tandem with solar thermal energy capture and storage.

2)    The group is exploring a nanophotonic approach to splitting the solar spectrum, enabling ultra-high efficiency solar energy conversion. This research area focuses on low-loss photonic micro/nanostructures for sculpting the flow of light, leading to improved light absorption and more efficient use of the full solar spectrum.

3)    The group is studying two-dimensional transition metal chalcogenides and their quantum phenomena for use as semiconductor materials in ultra-thin optoelectronic devices. We have a particular interest in heterostructures of 2D materials and ternary transition metal chalcogenides.

The work in this group involves optical, thermal, and device physics simulations, micro/nanofabrication, and optoelectronic material and device characterization.

Top ⇑Quantum Information and Nonlinear Optics

Principal Investigator: Ryan T. Glasser

Tulane Group Members: Onur Danaci, Benjamin Sloan, and Christian Rios

Group Website

The Glasser group conducts experimental research in the closely related fields of quantum information and quantum optics. One core aspect of this research is to improve our understanding of the fundamental physics surrounding quantum entanglement and quantum states of light. A second aspect involves utilizing these concepts in various computation, communication, and measurement protocols to enhance performance beyond classical limits.

The fundamental process involved in this research is four-wave mixing in warm atomic vapor. This process generates pairs of photons in separate spatial modes that exhibit stronger correlations than allowed by classical physics, in multiple degrees of freedom. When a laser is used to seed the process, bright “twin beams” of light are created. The correlations in these “twin beam” states are exploited to enhance, for example, interferometric measurements and the resolution of imaging systems. Investigating novel methods to generate highly multimode “squeezed light” is an important aspect of this research area.

The group is also interested in the generation of novel high-dimensional entangled states of light. This work involves creating robust continuous-variable states that are applicable to real-world systems in which scattering and decoherence are present. The fundamental behavior of the quantum information present in these states is a key theme in this research.

Top ⇑Quantum Materials

Principal Investigator: Zhiqiang Mao

Tulane Group Members: Jin Hu, Jinyu Liu, Yanglin Zhu, Zhijie Tang, Jianjian Ge, Alyssa Chuang

Group Website

Emergent phenomena in quantum materials not only hold the promise for advanced applications in information technologies, but also challenge current knowledge in physics. The Mao group’s research at Tulane aims to discover and synthesize novel quantum materials with emergent phenomena and investigate their underlying physics. His current research is focused on four sub-directions: a) emergent quantum phenomena in strongly correlated oxides; b) interplay between magnetism and superconductivity in iron-based superconductors; c) novel functional two-dimensional (2D) materials of ternary transition metal chalcogenides; d) topological Dirac and Weyl semimetals.

The Mao group not only grows single crystals of quantum materials, but also performs various measurements to study the physics of quantum materials. For crystal growth, his group primarily uses the optical floating-zone, flux and chemical vapor transport methods. His group is capable of growing high quality single crystals of a wide range of materials, including complex oxides, various binary, ternary and quaternary transition metal intermetallic compounds (see the “Crystals” page in his group website for the list of materials his group has grown). In addition to material synthesis efforts, his group also performs electronic transport, magnetization and specific heat measurements to characterize and understand electronic, magnetic and thermodynamic properties of quantum materials. Furthermore, Mao has also established extensive collaborations with researches at other institutions and National Laboratories to study quantum materials using advanced techniques such as neutron scattering and photoemission spectroscopy.

Top ⇑Polymer Physics & Biophysics

Principal Investigator: Wayne Reed

Tulane Group Members: Mike Drenski, Colin McFaul, Zheng Li, Zifu Zhu

Group Website

Research in my group centers on fundamental and applied aspects of Polymer Science, with an increasing emphasis on private sector liaison. We study biological and synthetic polymers in solution, with an aim towards discovering basic physical principals involved in their structures and interactions, as well as solving practical problems of immediate interest to such industries as pharmaceuticals, biotechnology, food, paints, adhesives, resins, coating, water purification, etc. To this end we are also strongly involved in developing new characterization techniques and instrumentation for polymers, especially those involving light scattering.

Efforts are concentrated on innovative ways of monitoring processes occurring in polymer solutions in real time. We make extensive use of light scattering and other optical techniques, viscometry, size exclusion chromatography, and other auxiliary techniques (DSC, electron-microscopy, etc.). We have interests in the fundamental areas of polymer reaction kinetics and mechanisms, conformations, interactions and hydrodynamics, with a special focus on polyelectrolytes.

Top ⇑Femtosecond & Teraherz Spectroscopy

Principal Investigator: Diyar Talbayev

Tulane Group Members: Kate Heffernan, Shuai Lin, Shukai Yu, Skylar Deckoff-Jones, and Adam Kehoe

Group Website

We are interested in optical and electrical properties of complex materials, which include materials with strong electronic correlations (e.g. magnetic and superconducting transition metal oxides), multiferroic materials that combine ferroelectricity with magnetism, and artificial THz plasmonic structures. We use time-resolved optical and terahertz spectroscopy to probe low-energy magnetic, lattice, and electronic excitations that reveal the microscopic physics governing a material. Time-resolved spectroscopy employs femtosecond light pulses to perturb and manipulate the equilibrium state of solids and adds another dimension, the time domain, to expose the relationships between the fundamental interactions in a material.

Current research topics include:

1. Time-resolved studies of coupled spin and charge dynamics in multiferroic materials. The motivation for this work is the exploration of THz-frequency switching magnetic and ferroelectric domains and the understanding of the basic physics that governs the switching dynamics.

2. Time resolved and THz spectroscopy of quasiparticle dynamics in strong correlated electron systems, specifically magnetic and superconducting materials.

3. Properties of surface plasmons at THz frequencies, THz plasmonics. Plasmonics studies electromagnetic waves interacting with electrons inside materials, the interaction that is governed by Maxwell's equations. Out of this simplicity have emerged such fascinating phenomena as negative refraction and sub-wavelength light focusing. We are focusing on the most immediate uses of THz surface plasmons in high-sensitivity chemical and biological sensing.

Top ⇑Nanodevice Physics

Principal Investigator: Jiang Wei

Tulane Group Members: Chunlei Yue, Xue Liu, Jake Smith

Group Website

The Wei group's research interest focuses on nanoscale condensed matter physics, particularly on the underlying physics of the emerging quantum phenomena in nanostructures. Nanodevice physics fascinates us because when the characteristic length of physical systems approaches to nanoscale, quantum mechanical effects start to appear or even dominate. We are primarily interested in two groups of nanostructured materials: 1D and 2D quantum materials, and strongly correlated materials. We utilize our state-of-the-art micro-nano fabrication facilities to transform these materials into measureable nanoscale devices. Because low-dimensional material exhibits different physical properties from those of bulk material, we investigate the electrical, magnetic, and optical properties of low-dimensional structures to understand the fundamental physics. The nanostructured devices of strongly correlated material can be used as a research vehicle to explore the unknown territory of phase diagram, to investigate the collective many-body behavior, and to manipulate the phase transition by applying electric field, magnetic field, strain, and chemical doping. We also explore the technological applications of these nanodevices.

Current research directions:

  • Quantum transport study of 1D and 2D materials
  • Investigation of the phase transition on nanostructured strongly correlated materials modulated by mesoscopic strain and chemical doping engineering.
  • Scanning photocurrent and surface enhanced Raman spectroscopy on nanodevices.
  • Development of fabrication technique of ultra-small nanostructures.

Top ⇑Experimental Nuclear Physics

Principal Investigator: Fred Wietfeldt

Tulane Group Members: Alexander Laptev,Taufique Hassan, Chandra Shahi

My group is engaged in experimental nuclear physics research using cold and ultracold neutrons. This work falls into three related, but distinct categories:

  1. Tests of the Electroweak Standard Model with precision measurements of neutron decay parameters
  2. Studies of the hadronic weak interaction by measuring parity-violating parameters in neutron interactions with matter
  3. Tests of nucleon forces and fundamental quantum mechanics using neutron interferometery.

    Our main focus right now is on categories (1) and (3).

Cold neutrons are free neutrons that are moving so slowly (less than 2000 m/s) that their deBroglie wavelengths are larger than the spacing between atoms in matter, typically in the range 0.2 to 2.0 nm. In this regime the neutron-matter interaction is coherent, the neutron interacts with many atoms simultaneously, and so it is more wave-like than particle-like. Cold neutrons can be manipulated optically, in many ways similar to light optics. They can be reflected, refracted, and diffracted in matter. Neutron guides, analogous to fiber optic guides, can be used to transport cold neutrons long distances with very little losses.

Ultracold neutrons (UCN's) are neutrons whose kinetic energy is less than about 300 neV. This energy is comparable to three important energy scales:

  1. The neutron's optical potential in certain materials;
  2. The neutron's potential energy in a strong magnetic field (~ 5 Tesla);
  3. The neutron's gravitational potential energy at a height of several meters. Therefore UCN's can be trapped optically, magnetically, and gravitationally. A free neutron will decay into a proton, electron, and antineutrino with a lifetime of about 15 minutes. This is the simplest nuclear beta decay and the prototype semi-leptonic weak decay. The measurable parameters of neutron decay such as its lifetime and angular correlations can be directly related to fundamental parameters in the Electroweak Standard Model. Precision experiments can test the self-consistency of the theory and possibly point to new physics related to grand unification. In this way neutron decay plays an important role in the low-energy frontier of particle physics.

Precise measurements of neutron scattering lengths using a neutron interferometer can be used to improve our understanding of the nucleon-nucleon potential and other parameters such as the charge radius of the neutron. The neutron interferometer is also used for fundamental tests of quantum mechanics. These experiments are carried out at the National Institute of Standards and Technology (NIST) (Center for Neutron Research). In addition to comprehensive instrumentation for neutron scattering research, this facility supports and operates a suite of neutron beams (both monochromatic and polychromatic) dedicated to fundamental neutron physics. It also operates the most sensitive Neutron Interferometer in the world.

We design and develop experiments in our laboratories at Tulane, usually in collaboration with groups at other institutions, and then bring experiments to NIST for data collection. We usually spend summers at NIST and students in my group often spend one or more years full time at NIST, after completing their Tulane course-work, to complete their dissertation research.

Upcoming experiments:

  • A measurement of the radiative decay branch of the neutron (never before observed)
  • A precision measurement of the electron-antineutrino correlation (little "a") in neutron decay
  • A precision measurement of the neutron-electron scattering length. This will lead to a determination of the charge radius of the neutron
  • An improved measurement of the neutron scattering length in polarized 3He gas. This will provide important and unique information about nucleon-nucleon forces.
  • A new measurement of gravitationally-induced quantum interference in a neutron interferometer. This tests the weak equivalence principle at the quantum limit.

2001 Percival Stern Hall, New Orleans, LA 70118, 504-865-5520