Exploring many-body phenomena through molecular nanostructures on surfaces

Abstract

The electronic structure of organic molecules, particularly polycyclic conjugated hydrocarbons, can be precisely tailored through a rational design of molecular size, shape, and atomic structure of the edges. This tunability enables the emergence of unusual properties such as magnetism.

In this talk, Shantanu Mishra will show that open-shell polycyclic conjugated hydrocarbons on surfaces serve as a versatile platform to construct and explore strongly correlated quantum phenomena.

Using thermally induced on-surface chemistry, he will demonstrate the synthesis of all-organic S = 1 antiferromagnetic quantum spin chains on a gold surface. A systematic investigation of length-dependent magnetic excitations via tunneling spectroscopy reveals gapped spin excitations in the bulk of the chains, with the gap saturating for sufficiently long chains, and fractional S = 1/2 excitations at the chain termini.

These spectral features provide direct experimental evidence of one of the cornerstone models in quantum magnetism: the Haldane phase.

He will further show that strong correlations can also emerge at the single-molecule scale. In particular, the synthesis of organic diradicals on thin insulating films by scanning probe tip-induced chemistry reveals unusual properties such as ground-state bistability.

About the speaker

Shantanu Mishra is an Assistant Professor at the Department of Chemical Physics, Physics and Astronomy at Chalmers University of Technology. His research focuses on molecular nanostructures on surfaces and their potential to explore quantum phenomena, including magnetism and strongly correlated electronic states.