Theory of Surface Polarons

We investigate the effect of charge carrier interaction with surface optical phonons on the band properties of monolayer black phosphorus induced by polar substrates. We develop an analytical method based on the Lee-Low-Pines theory to calculate the spectrum of Fröhlich type continuum Hamiltonian in the long-wavelength limit. We examine the modification of a band gap and renormalization of effective masses due to the substrate-related polaronic effect. Our results show that an energy gap in supported monolayer black phosphorus is enlarged depending on a particular substrate and the interlayer distance, z. Among the substrate considered, the largest gap broadening at z = 2.5Å is observed for the Al2O3 substrate, which is found to be ∼ 50 meV. Carrier-phonon coupling also renormalizes the effective masses which is more pronounced along the zigzag direction. Anisotropy of the effective masses becomes stronger by the influence of the polaronic effect corresponding to direction-dependent carrier-phonon coupling. We conclude that substrate phonons have a non-negligible effect on the static band properties of monolayer black phosphorus, which may be further exploited in its experimental and theoretical studies.

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“…where M µq = e 2 ξ ω µ /2A 0 qe −qz is the amplitude of carrier-surface optical phonon interaction [42][43][44]…”

Section: Theorymentioning

confidence: 99%

Polaronic effects in monolayer black phosphorus on polar substrates

Moğulkoç

Руденко³

et al. 2016

Phys. Rev. B

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“…The interaction between the carriers and the polar interface is described by the following Fröhlich Hamiltonian [1,4,5] …”

Section: Polaron Formationmentioning

confidence: 99%

Electron–phonon and electron–electron interactions in organic field effect transistors

Fratini

Morpurgo

Ciuchi

2008

Journal of Physics and Chemistry of Solids

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Recent experiments have demonstrated that the performances of organic FETs strongly depend on the dielectric properties of the gate insulator. In particular, it has been shown that the temperature dependence of the mobility evolves from a metallic-like to an insulating behavior upon increasing the dielectric constant of the gate material. This phenomenon can be explained in terms of the formation of small polarons, due to the polar interaction of the charge carriers with the phonons at the organic/dielectric interface. Building on this model, the possible consequences of the Coulomb repulsion between the carriers at high concentrations are analyzed.

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“…The influence of surface phonons on the electron polaronic state inside the ionic crystal has been studied long time ago [7]. Here we address the opposite situation when the electron resides in the non-polar media (e.g.…”

Section: Surface Long Range Polarons In Molecular Crystalsmentioning

confidence: 99%

Electronic states at junctions of molecular semiconductors

Kirova¹

2008

Journal of Physics and Chemistry of Solids

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We consider properties of junctions for the FET geometry where molecular crystals or conducting polymers are used as semiconducting layers. In the molecular crystal Coulomb interaction of free electrons with surface polar phonons of the dielectric layer can lead to selftrapping of carriers and to the formation of a strongly coupled long-range surface polaron. The effect is further enhanced at presence of the bias electric field and strongly depends on the gate dielectric used. In conducting polymers instead of the usual band bending near the contact interface, new allowed electronic bands appear inside the band gap. As a result the bias electric field and the injected charge penetrate into the polymer via creation of the soliton lattice whose period changes with the distance from the contact surface. The current through the contact is performed via moving solitons.

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Theory of Surface Polarons

Cited by 139 publications

References 11 publications

Polaronic effects in monolayer black phosphorus on polar substrates

Polaronic effects in monolayer black phosphorus on polar substrates

Electron–phonon and electron–electron interactions in organic field effect transistors

Electronic states at junctions of molecular semiconductors

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