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arXiv · 1910.01848

Momentum-resolved linear dichroism in bilayer MoS$_2$

Klara Volckaert·Habib Rostami·Deepnarayan Biswas·Igor Marković·Federico Andreatta·Charlotte E. Sanders·Paulina Majchrzak·Cephise Cacho·Richard T. Chapman·Adam Wyatt·Emma Springate·Daniel Lizzit·Luca Bignardi·Silvano Lizzit·Sanjoy K. Mahatha·Marco Bianchi·Nicola Lanata·Phil D. C. King·Jill A. Miwa·Alexander V. Balatsky·Philip Hofmann·Søren Ulstrup
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Abstract

Inversion-symmetric crystals are optically isotropic and thus naively not expected to show dichroism effects in optical absorption and photoemission processes. Here, we find a strong linear dichroism effect (up to 42.4%) in the conduction band of inversion-symmetric bilayer MoS$_2$, when measuring energy- and momentum-resolved snapshots of excited electrons by time- and angle-resolved photoemission spectroscopy. We model the polarization-dependent photoemission intensity in the transiently-populated conduction band using the semiconductor Bloch equations and show that the observed dichroism emerges from intralayer single-particle effects within the isotropic part of the dispersion. This leads to optical excitations with an anisotropic momentum-dependence in an otherwise inversion symmetric material.

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Klara Volckaert, Habib Rostami, Deepnarayan Biswas, Igor Marković, Federico Andreatta, Charlotte E. Sanders, Paulina Majchrzak, Cephise Cacho, Richard T. Chapman, Adam Wyatt, Emma Springate, Daniel Lizzit, Luca Bignardi, Silvano Lizzit, Sanjoy K. Mahatha, Marco Bianchi, Nicola Lanata, Phil D. C. King, Jill A. Miwa, Alexander V. Balatsky, Philip Hofmann, Søren Ulstrup. 2019-10-04. Momentum-resolved linear dichroism in bilayer MoS$_2$. https://doi.org/10.1103/physrevb.100.241406

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