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

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

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Date

08/05/2018

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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

Werdehausen , D , Agustsson , S Y , Kim , M , Shabestari , P , Huang , E , Pokharel , A , Larkin , T , Boris , A , Takayama , T , Lu , Y , Rost , A W , Chu , H , Yaresko , A , Höppner , M , Schulz , A , Manske , D , Keimer , B , Takagi , H & Kaiser , S 2018 , Ultrafast dynamics and coherent order parameter oscillations under photo-excitation in the excitonic insulator Ta 2 NiSe 5 . in M K Rafailov (ed.) , Ultrafast Bandgap Photonics III . , 1063803 , Proceedings of SPIE , vol. 10638 , SPIE , pp. 1-7 , Ultrafast Bandgap Photonics III 2018 , Orlando , Florida , United States , 16/04/18 . https://doi.org/10.1117/12.2304795

conference

Publication

Ultrafast Bandgap Photonics III

DOI

https://doi.org/10.1117/12.2304795

ISSN

0277-786X

Type

Conference item

Rights

Copyright © 2018 SPIE. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at https://doi.org/10.1117/12.2304795

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University of St Andrews Research

URI

http://hdl.handle.net/10023/18974