Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations

Некрасов, И. А.; Павлов, Н. С.; Sadovskiǐ, M. V.

doi:10.1134/s1063776118040106

Cited by 20 publications

(10 citation statements)

References 69 publications

(89 reference statements)

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“…[14,24]). The measured band dispersions of monolayer FeSe could thus far not be reproduced by correlated band-theory calculations as dynamical mean field theory (DMFT) [29,30]. As the here-used tight-binding bands provide a very good description of the bands in the near-Fermi energy region we therefore preferred to use these.…”

Section: Resultsmentioning

confidence: 99%

Self-consistent temperature dependence of quasiparticle bands in monolayer FeSe on SrTiO3

2018

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We study the temperature evolution of the quasiparticle bands of the FeSe monolayer on the SrTiO3 (STO) substrate from 10 to 300 K by applying the anisotropic, multiband and full-bandwidth Eliashberg theory. To achieve this, we extend this theory by self-consistently coupling the chemical potential to the full set of Eliashberg equations. In this way, the electron filling can accurately be kept at a constant level at any temperature. Solving the coupled equations self-consistently, and with focus on the interfacial electron-phonon coupling, we compute a nearly constant Fermi surface with respect to temperature and predict a non-trivial temperature evolution of the global chemical potential. This evolution includes a total shift of 5 meV when increasing temperature from 10 to 300 K and a hump-like dependence followed by a kink at the critical temperature Tc. We argue that the latter behavior indicates that superconductivity in FeSe/SrTiO3 is near to the BCS-BEC crossover regime. Calculating the temperature dependent Angle Resolved Photoemission Spectroscopy (ARPES) spectra, we suggest a new route to determine the energy scale of the interfacial phonon mode by measuring the energy position of second-order replica bands. Further, we reexamine the often used symmetrization procedure applied to such ARPES curves and demonstrate substantial asymmetric deviations. Lastly, our results reveal important aspects for the experimental determination of the momentum anisotropy of the superconducting gap.

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Section: Resultsmentioning

confidence: 99%

Self-consistent temperature dependence of quasiparticle bands in monolayer FeSe on SrTiO3

2018

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“…Proper treatment of them requires a separate study. Some success in this direction was achieved within the LDA+DMFT (local density approximation+dynamical mean field theory) studies [69,70] 4 Conclusions…”

Section: Resultsmentioning

confidence: 99%

Effect of the Additional Se Layer on the Electronic Structure of Iron-Based Superconductor FeSe/SrTiO3

Tikhonova

Korshunov

2019

J Supercond Nov Magn

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We use density functional theory to study the structure and the band structure of the monolayer FeSe deposited on the SrTiO 3 substrate with the additional layer of Se between them. Top of the SrTiO 3 is formed by the double TiO layer with and without oxygen vacancies. Several structures with different arrangements of the additional Se atoms above the double TiO layer is considered. Equilibrium structures were found and the band structures for them were obtained. Near the Γ = (0, 0, 0) point of the Brillouin zone, the hole Fermi surface pockets persist and, additionally, an electron pocket appears. Thus neither the presence of the additional Se layer nor the oxygen vacancies in the double TiO layer leads to the sinking of hole bands below the Fermi level near the Γ point. Necessity to include the strong electronic correlations into account is discussed.Keywords Fe-based superconductors · Monolayer FeSe · SrTiO 3 · density functional theory 1 IntroductionIron-based materials represents a class of high-T c superconductors that is based on the conducting layer

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“…Therefore, two essential generic questions concerning the carrier density in correlated semimetals are 1) what key factors control the carrier density variation in these systems, and 2) how the carrier density is able to vary so efficiently against change of "weak" external conditions, for example temperature, pressure, or magnetic field. The strongest correlation due to strong intra-atomic repulsion is known to be able to enhance the effective mass of carriers [24][25][26][27] (which can potentially modify the carrier density in semimetals). However, the large energy scale of the local repulsion dictates that such mass enhancement is rather robust and thus unable to vary sensitively by "weak" (or low-energy) external conditions.…”

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confidence: 99%

Variation of carrier density in semimetals via short-range correlation: a case study with nickelate NdNiO$_2$

Jiang¹,

Lang²,

Berlijn³

et al. 2022

Preprint

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Carrier density is one of the key controlling factors of material properties, particularly in controlling the essential correlations in strongly correlated materials. Typically, carrier density is externally tuned by doping or gating, and remains fixed below room temperature. Strangely, the carrier density in correlated semimetals is often found to vary sensitively to the external controls of small energy scale, such as temperature, magnetic field, and pressure. Here using the recently discovered nickelate superconductor as an example, we demonstrate a rather generic low-energy mechanism that short-range (non-collinear magnetic) correlation can reversely modulate the carrier density as well. Such a mutual influence between correlation and carrier density provides an extra ingredient for bifurcation of emergent phenomena. This special feature of correlated semimetals explains their versatile carrier density at low energy, and opens up new possibilities of functionalizing these materials.

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Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations

Cited by 20 publications

References 69 publications

Self-consistent temperature dependence of quasiparticle bands in monolayer FeSe on SrTiO3

Self-consistent temperature dependence of quasiparticle bands in monolayer FeSe on SrTiO3

Effect of the Additional Se Layer on the Electronic Structure of Iron-Based Superconductor FeSe/SrTiO3

Variation of carrier density in semimetals via short-range correlation: a case study with nickelate NdNiO$_2$

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