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arXiv · 1911.09118

Evidence of Rotational Fr\"ohlich Coupling in Polaronic Trions

Maxim Trushin·Soumya Sarkar·Sinu Mathew·Sreetosh Goswami·Prasana Sahoo·Yan Wang·Jieun Yang·Weiwei Li·Judith L. MacManus-Driscoll·Manish Chhowalla·Shaffique Adam·T. Venkatesan
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Abstract

Electrons commonly couple through Fr\"ohlich interactions with longitudinal optical phonons to form polarons. However, trions possess a finite angular momentum and should therefore couple instead to rotational optical phonons. This creates a polaronic trion whose binding energy is determined by the crystallographic orientation of the lattice. Here, we demonstrate theoretically within the Fr\"ohlich approach and experimentally by photoluminescence emission that the bare trion binding energy (20 meV) is significantly enhanced by the phonons at the interface between the two-dimensional semiconductor MoS$_2$ and the bulk transition metal oxide SrTiO$_3$. The low-temperature {binding energy} changes from 60 meV in [001]-oriented substrates to 90 meV for [111] orientation, as a result of the counter-intuitive interplay between the rotational axis of the MoS$_2$ trion and that of the SrTiO$_3$ phonon mode.

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Maxim Trushin, Soumya Sarkar, Sinu Mathew, Sreetosh Goswami, Prasana Sahoo, Yan Wang, Jieun Yang, Weiwei Li, Judith L. MacManus-Driscoll, Manish Chhowalla, Shaffique Adam, T. Venkatesan. 2019-11-20. Evidence of Rotational Fr\"ohlich Coupling in Polaronic Trions. https://doi.org/10.1103/physrevlett.125.086803

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