THz-Frequency Modulation of the Hubbard $U$ in an Organic Mott Insulator

R. Singla, G. Cotugno, S. Kaiser, M. Först, M. Mitrano, H. Y. Liu, A. Cartella, C. Manzoni, H. Okamoto, T. Hasegawa, S. R. Clark, D. Jaksch, and A. Cavalleri

Phys. Rev. Lett. 115, 187401 – Published 29 October 2015

Abstract

We use midinfrared pulses with stable carrier-envelope phase offset to drive molecular vibrations in the charge transfer salt $ET − F_{2} TCNQ$ , a prototypical one-dimensional Mott insulator. We find that the Mott gap, which is probed resonantly with 10 fs laser pulses, oscillates with the pump field. This observation reveals that molecular excitations can coherently perturb the electronic on-site interactions (Hubbard $U$ ) by changing the local orbital wave function. The gap oscillates at twice the frequency of the vibrational mode, indicating that the molecular distortions couple quadratically to the local charge density.

Received 3 September 2014

DOI:https://doi.org/10.1103/PhysRevLett.115.187401

Physics Subject Headings (PhySH)

Electrical conductivity

Mott insulators Organic compounds

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

R. Singla^1,*, G. Cotugno^1,2, S. Kaiser^1,7,8,†, M. Först¹, M. Mitrano¹, H. Y. Liu¹, A. Cartella¹, C. Manzoni^1,4, H. Okamoto⁵, T. Hasegawa⁶, S. R. Clark^2,9, D. Jaksch^2,3, and A. Cavalleri^1,2,‡

¹Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
²Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, OX1 3PU Oxford, United Kingdom
³Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
⁴IFN-CNR, Dipartimento di Fisica-Politecnico di Milano, Milan, Italy
⁵Department of Advanced Material Science, University of Tokyo, Chiba 277-8561, Japan
⁶National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8562, Japan
⁷Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
⁸4th Physics Institute, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
⁹Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom

^*rashmi.singla@mpsd.mpg.de
^†s.kaiser@fkf.mpg.de
^‡andrea.cavalleri@mpsd.mpg.de

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 115, Iss. 18 — 30 October 2015

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Physical Review Letters