Frustrationsdriven c 4 symmetrisk ordning i en naturligt

Supraledning vid hög temperatur - High-temperature

We found that Cs deposition enables heavily electron doping into the FeSe layer. In properly doped films, we also revealed the occurrence of superconductivity accompanied by the suppression of electronic nematicity. We performed ARPES measurements in order to demonstrate experimentally the existence of the Γ − 2 band with strong p z orbital character crossing E F along the Γ-Z direction.Large single-crystals of FeSe 0.45 Te 0.55 were grown using the self-flux method, and LiFeAs with FeAs flux method. ARPES measurements were performed at the Advanced Light Source and Synchrotron Radiation Center, using We report results on epitaxial FeSe thin films grown by pulsed laser deposition (PLD) on CaF2 (001) substrates as obtained by exploiting the advantages of an all-in-situ ultra-high vacuum (UHV) laboratory allowing for direct high-resolution surface analysis by scanning tunnelling microscopy (STM), synchrotron radiation X-ray photoelectron spectroscopy (XPS) and angle-resolved photoemission The FeSe superconductor and its related systems have attracted much attention in the iron-based superconductors owing to their simple crystal structure and peculiar electronic and physical properties. The bulk FeSe superconductor has a superconducting transition temperature (Tc) of ~8 K; it can be dramatically enhanced to 37 K at high pressure. 2015-09-08 ARPES and inelastic neutron spectra measured on twinned and detwinned FeSe [15, 46, 66]. (a) ARPES spectra taken along the Γ - M direction on a twinned FeSe.

Arpes fese

A phase diagram and The first ARPES study on single-layer FeSe/STO films has provided key insights substrate by means of angle-resolved photoemission spectroscopy (ARPES). The first ARPES study on single-layer FeSe/STO films has provided key insights into the electronic origin of superconductivity in this system. A phase diagram The first ARPES study on single-layer FeSe/STO films has provided key insights into the electronic origin of superconductivity in this system. A phase diagram can be used to simulate several experimental quantities like e.g. ARPES and MgB2 and H-MgB2 monolayers, heterostructures like FeSe/SrTiO3, high-Tc av A Aperis — theory calculations for a monolayer FeSe on SrTiO3 highlight the importance of Evaluates experimental quantities like ARPES, STS and London penetration Eliashberg theory for spin fluctuation mediated superconductivity: Application to bulk and monolayer FeSe2020Ingår i: Physical Review B, ISSN 2469-9950, såsom STM och vinkel-löst photoemission spektroskopi (ARPES), angle-resolved photo-emission spectroscopy measurements of FeSe.

Alex Aperis - Uppsala University, Sweden

We report high resolution angle-resolved photo-emission spectroscopy (ARPES) measurements of detwinned FeSe single crystals. The application of a mechanical strain is used to promote the volume 2019-10-02 · However, correlations strongly renormalize the bands compared to electronic structure calculations, and there is no evidence for the expected bulk band inversion.

Allestädes närvarande stark elektron-fonon-koppling vid

This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under contract Abstract: We report high resolution ARPES measurements of detwinned FeSe single crystals. The application of a mechanical strain is used to promote the volume fraction of one of the orthorhombic domains in the sample, which we estimate to be 80$\%$ detwinned. We report high resolution ARPES measurements of detwinned FeSe single crystals. The application of a mechanical strain is used to promote the volume fraction of one of the orthorhombic domains in the sample, which we estimate to be 80% detwinned.

Based on a series of ARPES measurements to investigate the effect of film thickness on the electron structure, Tan et al.
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[37] found the FSs of the monolayer FeSe film and the multilayer FeSe film were significantly different ( Fig. 12 ). Recent ARPES results show that after FeSe films enter the high-T c phase via surface K dosing, the electron correlation anomalously increases upon further doping, and eventually, an insulating phase emerges . This indicates remarkable complexity and new physics in the “overdoped” region. FeSe is a fascinating superconducting material at the frontier of research in condensed matter physics.

The application of a mechanical strain is used to promote the volume fraction of one of the orthorhombic domains in the sample, which we estimate to be detwinned. The observation of replica bands in single-unit-cell FeSe on SrTiO3 (STO)(001) by angle-resolved photoemission spectroscopy (ARPES) has led to the conjecture that the coupling between FeSe ARPES: schematic Fermi surfaces of FeSe –3D Tetragonal phase: smaller pockets and band renormalisations. Nematic phase: the hole pocket distorts, one elongated electron pocket seen by ARPES.
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Selfconsistent Theory of Superconductivity - Department of

INTRODUCTION 2012-07-03 · Direct-ARPES and STM Investigation of FeSe Thin Film Growth by Nd:YAG Laser Sandeep Kumar Chaluvadi, Debashis Mondal, Chiara Bigi, Jun Fujii, Rajdeep Adhikari, Regina Ciancio Phase diagram of FeSe 1 − x S x and the suppression of electronic correlations by S substitution. (a) The ARPES map of the high-symmetry cut through top of the Brillouin zone for the tetragonal phase of FeSe 1 − x S x (x = 0, 0.18, 1) at 56–69 eV, together with a calculated slice for FeS in (b). The solid line indicates the cuts used during ARPES experiments.

Effekten av nematisk beställning på fese elektronisk struktur

By probing detwinned crystals with different linear polarizations of their pulsed laser system (250 fs time resolution), they can selectively observe xz and yz orbital electrons. ARPES characterizations of 1UC FeSe/5UC LTO/STO films. a) Schematic diagram of the material structure. b) The Fermi surfaces of electron pockets near the zone corner M. Red lines indicate the Brillouin zone edges.

Bulk FeSe is an iron-based superconductor that has a maximum Tc of 8K. Surprisingly, the Tc of a single layer of FeSe film grown epitaxially on the SrTiO 3 substrate is enhanced to over 55K. We perform in-situ synchrotron-based MBE/ARPES experiment to understand how the transition temperature can be enhanced from the bulk superconducting transition temperature (Tc) of 8K at this 1UC FeSe/STO interface. Here, we report high resolution angle resolved photoemission spectroscopy (ARPES) results which reveal an unexpected and unique characteristic of the 1UC FeSe/STO system: each energy band of the FeSe film is almost exactly replicated at a fixed energy separation. Combining Angle resolved photoelectron spectroscopy (ARPES) and a μ-focused Laser, we have performed scanning ARPES microscopy measurements of the domain population within the nematic phase of FeSe single crystals. We are able to demonstrate a variation of the domain population density on a scale of a few 10 μmwhile constraining the upper limit of This is confirmed by performing ARPES on FeSe single crystals, whereby a 25-meV rigid chemical potential shift is detected across the entire Brillouin zone over the temperature range between 100 K and 300 K. The finding has important implications for any future theoretical models of nematicity and superconductivity in FeSe and related materials.