Materials Science Research Lecture

Wednesday April 21, 2021 4:00 PM

Quasi-1D Hexagonal Chalcogenides: From Giant Optical Anisotropy to Ultralow Glassy Thermal Conductivity

Speaker: Jayakanth Ravichandran, Chemical Engineering and Materials Science, Electrical and Computer Engineering, University of Southern California
Location: Online Event

Webinar Link:

https://caltech.zoom.us/j/95708772987

Webinar ID: 957 0877 2987

Abstract:

Perovskite Chalcogenides are a new class of semiconductors with very high absorption coefficient, giant optical anisotropy and tunable band gaps in the visible to infrared energies. In this talk, I will briefly summarize advances made both in my research group and in the research community on the theory, synthesis of these materials and understanding their physical properties. Among these materials, I will discuss the unconventional properties of quasi-1D hexagonal chalcogenides with face shared transition metal – chalcogen octahedra. First, I will outline the large linear optical anisotropy in these materials in terms of birefringence, dichroism, and linear dichroism conversion properties in the mid- to long-wave infrared energies. Second, I will discuss the observation of ultra-low glassy thermal conductivity in single crystals of these materials and a possible explanation for this observation. Third, I will elucidate our efforts to understand electronic transitions arising from the quasi-1D structure, how these observations can lead to novel electronic and photonic functionalities. Finally, I will provide a general outlook for future studies and applications of these exciting new class of materials.

References:

  • Nature Communications, 11, 6039 (2020).
  • Advanced Materials, 31 (33), 1902118 (2019).
  • Nature Photonics, 12, 392-396 (2018).
  • Chemistry of Materials, 30 (15), 4897-4901 (2018).
  • Chemistry of Materials, 30 (15), 4882-4886 (2018).
  • Advanced Materials 29, 1604733 (2017).
  • More about the Speaker:

    Jayakanth Ravichandran is an Assistant Professor in the Mork Family Department of Chemical Engineering and Materials Science with courtesy appointment in Ming Hsieh Department of Electrical and Computer Engineering at University of Southern California. He received his Ph.D. degree from University of California, Berkeley in 2011. He performed post-doctoral research at Columbia University and briefly at Harvard University, before joining the current position. His research interests are in materials design, synthesis, characterization, and physical properties of complex materials for electronic, photonic, and energy applications. His honors include the 2020 TMS Young Leader Professional Development Award, 2020 Orange County Engineering Council Outstanding Engineering Merit Award, and 2017 Early Career Scholar in Materials Science by the Journal of Materials Research.

    Series Materials Research Lecture Series

    Contact: Jennifer Blankenship jennifer@caltech.edu