About

The Instituto de Ciencia de Materiales de Madrid (ICMM) is an institute of the Consejo Superior de Investigaciones Cientificas (CSIC) (Spanish National Research Council) founded in December 1986, that belongs to the Area of Science and Technology of Materials, one of the eight Areas in which the CSIC divides its research activities.

 

Our mission is to create new fundamental and applied knowledge in materials of high technological impact, their processing and their transfer to the productive sectors at local, national and European scales (the true value of materials is in their use), the training of new professionals, and the dissemination of the scientific knowledge.

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Forthcoming Events

APR26/12:00

Moiré patterns and spontaneous deformations in 2D crystals
Pablo San-Jose  read more

MAY07/12:00

Viscosity of 2D Topological Phases
Barry Bradlyn  read more

MAY09/12:00

Resonancias ferromagnética y antiferromagnética de ondas de spin y transiciones de campo cristalino en RCrO3 (R= Pr, Sm, Er) a temperaturas ultrabajas en la región espectral THz
Néstor E. Massa  read more

Strain Control of Exciton–Phonon Coupling in Atomically Thin Semiconductors

Iris Niehues, Robert Schmidt, Matthias Drüppel, Philipp Marauhn, Dominik Christiansen, Malte Selig, Gunnar Berghäuser, Daniel Wigger, Robert Schneider, Lisa Braasch, Rouven Koch, Andres Castellanos-Gomez, Tilmann Kuhn, Andreas Knorr, Ermin Malic, et

Semiconducting transition metal dichalcogenide (TMDC) monolayers have exceptional physical properties. They show bright photoluminescence due to their unique band structure and absorb more than 10% of the light at their excitonic resonances despite their atomic thickness. At room temperature, the width of the exciton transitions is governed by the exciton–phonon interaction leading to strongly asymmetric line shapes. TMDC monolayers are also extremely flexible, sustaining mechanical strain of about 10% without breaking. The excitonic properties strongly depend on strain. For example, exciton energies of TMDC monolayers significantly redshift under uniaxial tensile strain. Here, we demonstrate that the width and the asymmetric line shape of excitonic resonances in TMDC monolayers can be controlled with applied strain. We measure photoluminescence and absorption spectra of the A exciton in monolayer MoSe2, WSe2, WS2, and MoS2 under uniaxial tensile strain. We find that the A exciton substantially narrows and becomes more symmetric for the selenium-based monolayer materials, while no change is observed for atomically thin WS2. For MoS2 monolayers, the line width increases. These effects are due to a modified exciton–phonon coupling at increasing strain levels because of changes in the electronic band structure of the respective monolayer materials. This interpretation based on steady-state experiments is corroborated by time-resolved photoluminescence measurements. Our results demonstrate that moderate strain values on the order of only 1% are already sufficient to globally tune the exciton–phonon interaction in TMDC monolayers and hold the promise for controlling the coupling on the nanoscale.

Nano Lett., 2018

ICMM-2018 - Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid, Spain. Tel: +34 91 334 9000. info@icmm.csic.es