Past colloquia and seminars


Tuning critical fluctuations in the excitonic insulator candidate Ta2NiSe5 by uniaxial strain

Academic or specialist Seminar

An excitonic insulating phase is predicted in narrow gapped semiconductors and semimetals, where electrons and holes driven by Coulomb interaction may sustain spontaneous condensation. The identification of the excitonic insulator state is challenging for the coexistence of a structural phase transition with the same symmetry breaking. Ta2NiSe5, being the most promising excitonic insulator candidate, is obscure to identify between an electronic origin of such phase transition, or a phonon driven scenario. Here we carried out electronic transport measurement under uniaxial strain applied by a piezo-based strain device, and Raman Scattering to study the strain-tuned behavior of the critical fluctuation as a quasi-elastic scattering in B2g symmetry, which could provide missing information on the relation of excitonic condensation and lattice dynamics.

When? 07.07.2023 14:00
Where? PER 08 0.51
Chemin du Musée 3
1700 Fribourg
speaker Xiaotong Shi
Max-Planck-Institute for Solid State Research, Stuttgart, Germany
Invited by group Bernhard
Contact Département de physique, groupe Bernhard
Prof. Christian Bernhard