Impact of electron-phonon interaction on the electronic structure of interfaces between organic molecules and a MoS$_2$ monolayer

Abstract

By means of first-principles calculations, we investigate the role of electron-phonon interaction in the electronic structure of hybrid interfaces, formed by MoS$_2$ and monolayers of the organic molecules pyrene and pyridine, respectively. Quasiparticle energies are initially obtained within the $G_0W_0$ approximation and subsequently used to evaluate the electron-phonon self-energy and momentum-resolved spectral functions to assess the temperature renormalization of the band structure. We find that the band-gap renormalization by zero-point vibrations of both hybrid systems is comparable to that of pristine MoS$_2$, with a value of approximately 80 meV. Pronounced features of molecular origin emerge in the spectral function of the valence region, which we attribute to satellites arising from out-of-plane vibrational modes of the organic monolayers. For pyrene, this satellite exhibits a predominantly molecular character, while for pyridine, it has a hybrid nature, originating from the coupling of molecular vibrations to the MoS$_2$ valence band.

Figures (3)

• Figure 1: Top: Temperature-dependent band structure of the MoS$_2$ monolayer for 0K (left) and 300K (right). The color scale bar, normalized to the global maximum across both temperatures, ranges from the minimum (white) to the maximum value (orange) of the spectral function. Middle: Spectral functions for the VBM and CBM at the K point, for temperatures up to 900K. Bottom: Temperature-dependence of the band gap. The QP gap obtained with the $G_0W_0$ approximation is indicated by the green dot.
• Figure 2: Top: Temperature-dependent band structure of pyrene@MoS$_2$ for 0K (left) and 300K (right). The color scale bar, normalized to the global maximum across both temperatures, ranges from the minimum (white) to the maximum (orange) value of the spectral function. Bottom: Spectral functions for valence and conduction bands at the $\Gamma$ point, for temperatures up to 500K.
• Figure 3: Top: Temperature-dependent band structure of pyridine@MoS$_2$ for 0K (left) and 300K (right). The color scale bar, normalized to the global maximum across both temperatures, ranges from the minimum (white) to the maximum (orange) value of the spectral function. Bottom: Spectral functions for valence and conduction bands at the $\Gamma$ point, for temperatures up to 500K.