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 and

Domain structure of FeSe. (a) Schematic of the experiment. Red and blue stripes represent domains with 90 • -rotated orthorhombic axes. Nano-ARPES measurements focus the photon beam to around 1

DFT calculation. One-ellipse effect preceding SDW in … High-resolution ARPES study of FeSe superconductors 著者 PHAN Giao Ngoc number 82 学位授与機関 Tohoku University 学位授与番号理博第3147号 Two recent ARPES studies have found a gap in single-layer FeSe/STO, which closes at 65 K and suggests a possible record high superconducting transition temperature (T c) of 65 K for FeHTSs FeSeZhou2 (); FeSeTan (); or at least, it is the pair-formation temperature record, if the superconducting transition there is a two dimensional Berezinskii-Kosterlitz-Thouless (BKT) type. 2021-02-17 High‐temperature superconductivity at the FeSe/SrTiO3 interface Yuan‐Yuan Xiang, Fa wang, DA Wang, Qiang‐Hua Wang, and Dong‐Hai Lee. Phys. Rev. B 86, 134508 (2012) Atomic and electronic structures of FeSe monolayer and bilayer thin films on SrTiO3(001): First‐principles study Kai … ARPES on Electronic Structure and Superconductivity of FeSe /SrTiO 3 Films Xingjiang ZHOU (周兴江) National Lab for Superconductivity Institute of Physics, Chinese Academy of Sciences, Beijing, China Strong Correlations and Unconventional Superconductivity: Towards a Conceptual Framework ， 2014/09/22--26, KITP, Santa Barbara spectroscopy (XPS) and angle-resolved photoemission spectroscopy (ARPES) on fresh surfaces. FeSe PLD growth protocols were ﬁne-tuned by optimizing target-to-substrate distance d and ablation frequency, atomically ﬂat terraces with unit-cell step heights are obtained, overcoming the spiral morphology often observed by others. 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.

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.

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 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). 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.

2020-03-03

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 2015-04-16 · The ARPES results on FeSe single crystals reported so far give a basically consistent picture [32, 67, 68], as exemplified in figure 4. First, at low temperature below the structural transition (~90 K), the Γ point is dominated by two hole-like bands (figure 4( f ) ), while near the M point, an electron-like band crossing the Fermi level and a hole-like band at higher binding energy are observed. toemission (ARPES) measurements on the single-layer FeSe/ SrTiO 3 films at various carrier concentrations. At a very low carrier concentration, the spectral weight near the Fermi level is suppressed, accompanied with the opening of an insulating energy gap. When the carrier concentration increases, the spectral 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 (ARPES) on fresh surfaces.

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. While the full structure of the electron pockets consisting of two crossed ellipses may be observed in the tetragonal phase at temperatures above 90 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. At a very low carrier concentration, the spectral 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 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).
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De tidigare detaljerade ARPES-mätningarna, som följde den elektroniska strukturutvecklingen Även om den verkliga Tc för FeSe S återstår att bekräftas genom transportmätningar in situ, hittade in situ -vinkelupplösta fotoemissionsspektroskopi (ARPES) Observationen av replikband i FeSe med en enhetscell på SrTiO 3 (STO) (001) med vinkelupplöst fotoemissionsspektroskopi (ARPES) har lett till antagandet att Den elektroniska strukturen av FeSe-filmer med enstaka lager på SrTiO 3 Detaljerad jämförelse av experimentella ARPES-data 10 för enkelskikt FeSe / STO Separationerna mellan de intilliggande FeAs / FeSe-skikten Δd är 8.741, 6.508, 6.364 ARPES-bandstrukturen för Li (Fe, Co) Som med 3% Co visas i figur 2e.

(c),(d) ARPES spectra taken on detwinned FeSe along the Γ−M X and Γ−M Y directions, respectively.
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av A Aperis — theory calculations for a monolayer FeSe on SrTiO3 highlight the importance of Evaluates experimental quantities like ARPES, STS and London penetration

(c),(d) ARPES spectra taken on detwinned FeSe along the Γ−M X and Γ−M Y directions, respectively. (e),(f) EDCs taken at the momentum pointed to by arrows in (b)–(d). All measurements are taken with 70 eV photons under odd polarization with respect to the cut direction. 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.