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Register a new userControlling spontaneous emission via electronic correlations in transparent metals
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Marcello Silva Neto Dr.
Publication date
2019
fields
Physics
and research's language is
English
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We study the spontaneous emission of agglomerates of two-level quantum emitters embedded in a correlated transparent metal. The characteristic emission energy corresponds to the splitting between ground and excited states of a neutral, nonmagnetic molecular impurity (F color center), while correlations are due to the existence of narrow bands in the metal. This is the case of transition metal oxides with an ABO3 Perovskite structure, such as SrVO3 and CaVO3, where oxygen vacancies are responsible for the emission of visible light, while the correlated metallic nature arises from the partial filling of a band with mostly d-orbital character. For these systems we put forward an interdisciplinary, tunable mechanism to control light emission governed by electronic correlations. We show that not only there exists a critical value for the correlation strength above which the metal becomes transparent in the visible, but also that strong correlations can lead to a remarkable enhancement of the light-matter coupling. By unveiling the role of electronic correlations in spontaneous emission, our findings set the basis for the design of controllable, solid-state, single-photon sources in correlated transparent metals.
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To clarify the nature of correlations in Hund metals and its relationship with Mott physics we analyze the electronic correlations in multiorbital systems as a function of intraorbital interaction U, Hunds coupling JH and electronic filling n. We show that the main process behind the enhancement of correlations in Hund metals is the suppression of the double-occupancy of a given orbital, as it also happens in the Mott-insulator at half-filling. However, contrary to what happens in Mott correlated states the reduction of the quasiparticle weight Z with JH can happen on spite of increasing charge fluctuations. Therefore, in Hund metals the quasiparticle weight and the mass enhancement are not good measurements of the charge localization. Using simple energetic arguments we explain why the spin polarization induced by Hunds coupling produces orbital decoupling. We also discuss how the behavior at moderate interactions, with correlations controlled by the atomic spin polarization, changes at large $U$ and $J_H$ due to the proximity to a Mott insulating state.
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