We present the results of detailed first principle electronic band structure calculations for these systems together with comparison with some experimental ARPES

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.

2017-05-05 · Thus the low temperature Fermi surface of FeSe as experimentally determined by ARPES consists of one elliptical hole pocket and one orthogonally-oriented peanut-shaped electron pocket. Our measurements clarify the long-standing controversies over the interpretation of ARPES measurements of FeSe. 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.

2017-05-08 2017-07-01 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. While the full structure of the electron pockets consisting of two crossed ellipses may be observed in the tetragonal phase at temperatures above 90 2020-03-03 2018-06-05 2015-07-15 In this Nature paper, T. Shimojima (RIKEN CEMS) et al. use time-resolved ARPES to visualize the ultrafast dynamics of electronic nematicity in FeSe. 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. This book mainly focuses on the study of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi2212) and single-layer FeSe film grown on SrTiO3 (STO) substrate by means of angle-resolved photoemission spectroscopy (ARPES). It provides the first electronic evidence for … Electronic anisotropies revealed by detwinned ARPES measurements of FeSe Matthew D. Watson,1, Amir A. Haghighirad,2 Luke C. Rhodes,1,3 Moritz Hoesch,1 and Timur K. Kim1, y 1Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom 2Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom 3Department of Physics, Royal … In fact, high resolution measurements of the electronic structure of FeSe by ARPES at beamline I05 at Diamond have previously made several important experimental contributions to the understanding FeSe is a fascinating superconducting material at the frontier of research in condensed matter physics.

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.

the low temperature Fermi surface of FeSe as experimentally determined by ARPES consists of one ellipti-cal hole pocket and one orthogonally-oriented peanut-shaped electron pocket. ARPES Studies of Monolayer FeSe on MBE Controlled Titanate Heterostructures. For 2D films, interface interactions can play a critical role in determining the prevailing physics of the system.

Although ARPES measurements indicated a the distinct pseudogap-like reduction in DOS in the hole pocket above \(T_{\text{c}}\), 116) no discernible reduction in DOS was observed in STS measurements. 142) The evolutions of the BCS–BEC crossover behavior in FeSe \(_{1-x}\) S x again suggest that a multiband system exhibits a unique feature that is absent in a single-band system.

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.

(a) ARPES spectra taken along the Γ - M direction on a twinned FeSe. (b,c) ARPES spectra taken on detwinned FeSe along the Γ - M X and Γ - M Y directions, respectively. (d,e) Energy distribution curves taken at the momentum pointed to by arrows in (a–c). We present a systematic angle-resolved photoemission spectroscopy study of the superconducting gap in FeSe. The gap function is determined in a full Brillouin zone including all Fermi surfaces and kz-dependence. We find significant anisotropy of the superconducting gap in all momentum directions. While the in-plane anisotropy can be explained by both, nematicity-induced pairing anisotropy and ARPES characterizations of 1UC FeSe/5UC LTO/STO films.
Apoteket stjärnan hudiksvall

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 spectroscopy … 2017-03-01 2017-05-05 2019-10-02 2017-06-09 Enabled by an angle-resolved photoemission spectroscopy beamline with a highly focused beam spot (nano-ARPES), we identify clear stripelike orthorhombic domains in FeSe with a length scale of 2012-07-03 We have revealed the existence of a novel electronic state in an highly unconventional multiband superconductor, FeSe, from the evolution of its electronic structure from the high-temperature tetragonal phase into the electronic nematic phase using angle resolved photoemission spectroscopy (ARPES).

Nematic phase: the hole pocket distorts, one elongated electron pocket seen by ARPES. DFT calculation In this paper, to our knowledge, we report the first observation of an insulator–superconductor crossover in the iron-based superconductors by performing systematic angle-resolved photoemission (ARPES) measurements on the single-layer FeSe/SrTiO 3 films at various carrier concentrations. We have revealed the existence of a novel electronic state in an highly unconventional multiband superconductor, FeSe, from the evolution of its electronic structure from the high-temperature tetragonal phase into the electronic nematic phase using angle resolved photoemission spectroscopy (ARPES).
Moderering

Here we present the influence of different STO surface terminations and photon energy dependent ARPES results which help to clarify the role of the substrate in the monolayer FeSe system. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under contract DE-AC02-76SF00515.

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.

Elsa modern fan art

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.

(b,c) ARPES spectra taken on detwinned FeSe along the Γ - M X and Γ - M Y directions, respectively. (d,e) Energy distribution curves taken at the momentum pointed to by arrows in (a–c). We present a systematic angle-resolved photoemission spectroscopy study of the superconducting gap in FeSe. The gap function is determined in a full Brillouin zone including all Fermi surfaces and kz-dependence. We find significant anisotropy of the superconducting gap in all momentum directions. While the in-plane anisotropy can be explained by both, nematicity-induced pairing anisotropy and ARPES characterizations of 1UC FeSe/5UC LTO/STO films.

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

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. DFT calculation 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.

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.