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Home  »  Colloquium   »   Enigma of two-dimensional melting in a disordered environment

Enigma of two-dimensional melting in a disordered environment

Date: 25/04/2024
Time & Venue: 5:30 PM, LH at UG Lab Block, PC

Speaker: Prof. Amit Ghosal, Department of Physics, IISER Kolkata

Title: Enigma of two-dimensional melting in a disordered environment

Abstract: We will present the results from our study of melting in a two-dimensional system of classical particles with Gaussian-core interactions in disordered environments. The clean system validates the conventional two-step melting with a hexatic phase intervening between the solid and the liquid. This picture gets significantly modified in disordered environments. Disorder, in the form of a random distribution of pinning centers, forces a hexatic-like low-temperature phase that transits into a liquid at a single melting temperature T_RP. In contrast, pinning centers located at randomly chosen sites of a perfect crystal anchor a solid at low temperatures, which undergoes a direct transition to the liquid at T_CP. Thus, the two-step melting is lost in either case of disorder. We will discuss the characteristics of melting depending on the nature of the impurities. The intriguing dynamical signatures of the system across melting, both in the presence and absence of impurities, will also be discussed.

About the Speaker: Prof. Amit Ghosal obtained his PhD in Theoretical Condensed Matter Physics from TIFR in 2001, followed by SHARCNet Postdoctoral fellow at McMaster University during 2000-2003. He was a Research Associate at Duke University (2003 – 2005) and a Saxon Postdoctoral Associate at the University of California Los Angeles (2005 – 2007). He joined IISER Kolkata as an Assistant Professor in 2008 and is currently a Professor there. He received the APS-IUSSTF Professorship Award in 2018 from the Indo-U.S. Science & Technology Forum (IUSSTF). His research focuses primarily on condensed phases of matter, in which the complex interplay of inter-particle interactions and intrinsic disorder in the material leads to intriguing emergent phenomena.