In: Physical Review B - Condensed matter and materials physics, 2012, vol. 85, no. 19, p. 195111
We present both theoretical ab-initio results within the Hedin's GW approximation and experimental angle-resolved photoemission and scanning tunneling spectroscopy measurements on TiSe₂. With respect to the density-functional Kohn-Sham metallic picture, the many-body GW self-energy leads to a ≈0.2-eV band-gap insulator consistent with our STS spectra at 5 K. The highest valence and the lowest...
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In: Physical Review B, 2019, vol. 99, no. 11, p. 115118
It is currently understood that high temperature superconductivity (SC) in the transition metal (M) substituted iron arsenides Ba(Fe1−xMx)2As2 is promoted by magnetic excitations with wave vectors (π,0) or (0,π). It is known that while a small amount of Co substitution lead to SC, the same does not occur for Mn for any value of x. In this work, magnetic excitations in the iron arsenides ...
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In: Physical Review B, 2013, vol. 88, no. 7, p. 075138
We address the question of the origin of the recently discovered chiral property of the charge-density-wave phase in 1T-TiSe₂, which so far lacks a microscopic understanding. We argue that the lattice degrees of freedom seem to be crucial for this novel phenomenon. We motivate a theoretical model that takes into account one valence and three conduction bands, a strongly screened Coulomb...
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In: Communications Physics, 2018, vol. 1, no. 1, p. 45
The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity. In bulk YBa2Cu3O7−δ the Cu-CDW is incipient and mainly pinned by defects. Nevertheless, a large magnetic field can induce a true long-range Cu- CDW order as it suppresses superconductivity. An enhanced Cu-CDW order was also ...
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In: Europhysics Letters, 2010, vol. 92, no. 4, p. 47003
We present angle-resolved photoemission experiments on 1T-TiSe₂ at temperatures ranging from 13 K to 288 K. The data evidence a dramatic renormalization of the conduction band below 100 K, whose origin can be related to the new potential responsible for the charge density wave phase at low temperature in this system. The renormalization translates into a substantial effective mass...
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In: Physical Review B - Condensed Matter and Materials Physics, 2012, vol. 85, no. 23, p. 235150
To address the fluctuation regime above the critical temperature of the charge-density-wave phase of 1T-TiSe₂, we perform calculations using the Bethe-Salpeter equation for treating strong electron-hole correlations. Calculated photoemission intensity maps are in good agreement with the measured ones and provide a deeper understanding of the phase transition in terms of an electronic...
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In: Physical Review B, 2020, vol. 101, no. 23, p. 235120
In the transition metal dichalcogenide IrTe2, low-temperature charge-ordered phase transitions involving Ir dimers lead to the occurrence of stripe phases of different periodicities, and nearly degenerate energies. Bulk-sensitive measurements have shown that, upon cooling, IrTe2 undergoes two such first-order transitions to (5×1×5) and (8×1×8) reconstructed phases at Tc1∼280 K and...
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In: Physical Review Letters, 2011, vol. 106, no. 10, p. 106404
We address the lattice deformation of 1T-TiSe₂ within the exciton condensate phase. We show that, at low temperature, condensed excitons influence the lattice through electron-phonon interaction. It is found that at zero temperature, in the exciton condensate phase of 1T-TiSe₂, this exciton condensate exerts a force on the lattice generating ionic displacements comparable in amplitude to what...
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In: Physical Review Letters, 2015, vol. 114, no. 8, p. 086402
Several experiments have been performed on 1T−TiSe2 in order to identify whether the electronic structure is semimetallic or semiconducting without reaching a consensus. In this Letter, we theoretically study the impact of electron-hole and electron-phonon correlations on the bare semimetallic and semiconducting electronic structure. The resulting electron spectral functions provide a...
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In: The European Physical Journal B - Condensed Matter And Complex Systems, 2011, vol. 81, no. 4, p. 399-403
We explore the interplay between the elastic scattering of photoelectrons and the surface core level shifts with regard to the determination of core level binding energies in Au(111) and Cu3Au(100). We find that an artificial shift is created in the binding energies of the Au 4f core levels, that exhibits a dependence on the emission angle, as well as on the spectral intensity of the core...
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