Next Seminar 

A new topological monolayer

Monday August 4th 2025, 15h – A003

Invited speaker:

Qiong Ma

(Department of Physics, Boston College)

I will present experimental studies on the topological and correlated properties of monolayer TaIrTe4. First, I will discuss a dual quantum spin Hall (QSH) insulator, arising from the interplay between its single-particle topology and density-tuned correlations [1-2]. At charge neutrality, monolayer TaIrTe4 exhibits QSH insulator behavior, characterized by enhanced nonlocal transport and quantized helical edge conductance. Upon introducing electrons from charge neutrality, TaIrTe4 only shows metallic behavior in a small range of charge densities but quickly goes into a new insulating state. This insulating state could arise from a strong electronic instability near the van Hove singularities, e.g., a charge density wave. Within this correlated insulating gap, we observe a resurgence of the QSH state. I will also discuss our recent efforts to study this correlated gap using nonlinear Hall responses.

[1] J. Tang, et al., Nature, 628, 515 (2024).
[2] J. Li, et al., arXiv:2506.18412 (2025).

Upcoming seminars

Past seminars

• Gerbold Menard (LPENS)

• Landry Bretheau (l'X)

• Eric Anderson (UW)

• Wilfrid Poirier (LNE)

• Emmanuel Baudin (LPENS)

• Zaki Legthas (LPENS)

• Mario Amado (University of Salamanca)

• Werner Wegscheider (ETH-Zurich)

• Danijela Marcovic (UMR-Thales)

• Mathieu Delbecq (LPENS)

• Jorge Vallejo-Bustamante (LPS)

• Liam Farrar (University of St. Andrews)

• Christophe Mora (Universite de Paris)

• Francois Parmentier (SPEC)

• Herve Aubin (C2N)

• Michael Manfra (Purdue University)

• Banan Kerdi (LNCMI-Toulouse)

• Abhishek Juyal (Neel Institute)

• Arthur Marguerite (College de France)

• Kamran Behnia (ESPCI)