The Theory of Topological Matter research team is a part of the Condensed Matter Theory Group of Institut Néel in Grenoble, France that is part of the CNRS, the largest governmental research agency in France.
Here are a few highlights of our recent research
Topological insulators respond to external fields in fundamentally different ways compared to trivial insulators. Combining topologically robust responses with the long history of large-scale growth and broad applications of amorphous materials, opens a door for technological progress. Here we propose models that are realistic and topological and display useful symmetry properties despite their lack of periodicity. They allow us to predict when amorphous topological phases occur and their physical responses, opening up a path to identify, classify, and discover amorphous topological insulators.
Quentin Marsal, Dániel Varjas, and Adolfo G. Grushin PNAS 117 (48) 30260 (2020)
The absence of mirror symmetry, or chirality, is behind striking natural phenomena found in systems as diverse as DNA and crystalline solids. A remarkable example occurs when chiral semimetals with topologically protected band degeneracies are illuminated with circularly polarized light. Under the right conditions, the part of the generated photocurrent that switches sign upon reversal of the light’s polarization, known as the circular photogalvanic effect, is predicted to depend only on fundamental constants. Here we investigate this possibility in the topological chiral semimetal CoSi, both theoretically and experimentally.
Zhuoliang Ni, K. Wang, Y. Zhang, O. Pozo, B. Xu, X. Han, K. Manna, J. Paglione, C. Felser, A. G. Grushin, F. de Juan, E. J. Mele, Liang Wu Nature Communications, 12, 154 (2021)
Another example of a chiral semimetals is RhSi. In this work, we report a comprehensive theoretical and experimental analysis of the linear and nonlinear optical responses of the chiral topological semimetal RhSi, which is known to host multifold fermions.
Zhuoliang Ni, B. Xu, M. A. Sanchez-Martinez, Y. Zhang, K. Manna, C. Bernhard, J. W. F. Venderbos, F. de Juan, C. Felser, A. G. Grushin, Liang Wu npj Quantum Materials 5, 96 (2020)