MRI: Development of a high-magnetic-field ultrafast and terahertz spectrometer for materials research in the Deep South

Tulane University, New Orleans LA

Investigators

Abstract

This award to Tulane University from the Major Research Instrumentation program and the Office of Multidisciplinary Activities of the Directorate for Mathematical and Physical Sciences supports the design and building of an advanced scientific tool for studying how matter and materials behave when they are placed in very strong magnetic field. This instrument will consist of two main parts: a very strong superconducting magnet and a set of lasers. Laser light will be used to probe how materials react to the strong magnetic field and to very low temperatures. Upon completion of the instrument development, the instrument will be available to outside user. The major science drivers of this instrument is in quantum matter, the advancement of our understanding of how electrons behave inside a wide variety of materials and imbue them with their properties, such as magnetism or superconductivity. Such basic scientific understanding underpins many technological marvels such as in medical diagnostic devices, computing chips in our phones and tablets, magnetic data storage technology, cell phone cameras, new energy-efficient LED light bulbs, and more. Through basic physics research, the proposed instrument will promote the progress of physics and advance national prosperity. This instrument will also contribute to advanced education of graduate and undergraduate students, thus building an educated national workforce for the new century. As a priority, the team of researchers promotes the participation in science and engineering fields of women and underrepresented minorities from Xavier University of Louisiana, a local Historically Black College or University. This award supports the development of a multi-user instrument for ultrafast terahertz (THz) spectroscopy in high magnetic fields of up to 17 T. The magnet cryostat provides the sample temperature control in the 2.5-300 K range and is cryogen-free. Four high-field experimental modalities will be available in both Faraday and Voigt optical configurations: i) THz time-domain spectroscopy based on photoconductive antennas with 0.2 - 3 THz spectral range; ii) time-resolved THz spectroscopy based on air-plasma THz generation and air-breakdown detection with 0.3 - 10 THz spectral range; iii) second harmonic generation with sample rotation about the surface normal; iv) optical pump-probe spectroscopy. The instrument will enable innovative research in magneto-electric excitations and optical nonreciprocity in multiferroics; search for the optical signatures of the chiral anomaly and the non-trivial band topology in Weyl semimetals; second harmonic generation and optical pump-probe studies of topological and magnetic materials; time-resolved THz spectroscopy of high-temperature superconducting pnictides. The instrument will become a part of the nationwide advanced research infrastructure. The instrument is unique, as it far outperforms in its specifications and capabilities other similar university-based research tools in the United States. In addition to eleven identified outside groups who have expressed a strong interest in the instrument capabilities in the nearest term.The instrument attracts potential local users and from across the Nation. The project contributes to the training of next the generation instrument developers. In the long run it will contribute to the education of dozens of graduate and undergraduate students. The project explicitly promotes the participation of women and underrepresented minorities in sciences and engineering. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.