Ultrafast dynamics and coherent order parameter oscillations under photo-excitation in the excitonic insulator Ta2NiSe5

Daniel Werdehausen; Steinn Ymir Agustsson; Minjae Kim; Parmida Shabestari; Emily Huang; Amrit Pokharel; Timofei Larkin; Alexander Boris; Tomohiro Takayama; Yangfan Lu; Andreas W. Rost; Hao Chu; Alexander Yaresko; Marc Höppner; Armin Schulz; Dirk Manske; Bernhard Keimer; Hidenori Takagi; Stefan Kaiser

doi:10.1117/12.2304795

8 May 2018 Ultrafast dynamics and coherent order parameter oscillations under photo-excitation in the excitonic insulator Ta₂NiSe₅

Daniel Werdehausen, Steinn Ymir Agustsson, Minjae Kim, Parmida Shabestari, Emily Huang, Amrit Pokharel, Timofei Larkin, Alexander Boris, Tomohiro Takayama, Yangfan Lu, Andreas W. Rost, Hao Chu, Alexander Yaresko, Marc Höppner, Armin Schulz, Dirk Manske, Bernhard Keimer, Hidenori Takagi, Stefan Kaiser

Author Affiliations +

Proceedings Volume 10638, Ultrafast Bandgap Photonics III; 1063803 (2018) https://doi.org/10.1117/12.2304795
Event: SPIE Defense + Security, 2018, Orlando, FL, United States

Abstract

The excitonic insulator (EI) is an intriguing phase of condensed excitons undergoing a Bose-Einstein-Condensation (BEC)-type transition. A prominent candidate has been identified in Ta₂NiSe₅. Ultrafast spectroscopy allows tracing the coherent response of the EI condensate directly in the time domain. Probing the collective electronic response we can identify fingerprints for the Higgs-amplitude equivalent mode of the condensate. In addition we find a peculiar coupling of the EI phase to a low frequency phonon mode. We will discuss the transient response on multiple energies scales ranging from the exciton dynamics to the coherent THz response of the gap.

Citation Download Citation

Daniel Werdehausen, Steinn Ymir Agustsson, Minjae Kim, Parmida Shabestari, Emily Huang, Amrit Pokharel, Timofei Larkin, Alexander Boris, Tomohiro Takayama, Yangfan Lu, Andreas W. Rost, Hao Chu, Alexander Yaresko, Marc Höppner, Armin Schulz, Dirk Manske, Bernhard Keimer, Hidenori Takagi, and Stefan Kaiser "Ultrafast dynamics and coherent order parameter oscillations under photo-excitation in the excitonic insulator Ta₂NiSe₅", Proc. SPIE 10638, Ultrafast Bandgap Photonics III, 1063803 (8 May 2018); https://doi.org/10.1117/12.2304795

ACCESS THE FULL ARTICLE