May 25, 2001
We have addressed the possibility of surface ferromagnetism in Sr2RuO4 by investigating its surface electronic states by angle-resolved photoemission spectroscopy (ARPES). By cleaving samples under different conditions and using various photon energies, we have isolated the surface from the bulk states. A comparison with band structure calculations indicates that the ARPES data are most readily explained by a nonmagnetic surface reconstruction.
Similar papers 1
December 1, 2000
We investigated the low-energy electronic structure of Sr2RuO4 by angle-resolved photoemission spectroscopy (ARPES) focusing, in particular, on the controversial issues of the Fermi surface (FS) topology and of the extended van Hove singularity (evHs). A detailed study of temperature and photon energy dependence demonstrates the surface-state nature of the electronic band responsible for the evHs, and may suggest the presence of ferromagnetic correlations at the surface. In a...
May 18, 2012
In search of the potential realization of novel normal-state phases on the surface of Sr2RuO4 - those stemming from either topological bulk properties or the interplay between spin-orbit coupling (SO) and the broken symmetry of the surface - we revisit the electronic structure of the top-most layers by ARPES with improved data quality as well as ab-initio LDA slab calculations. We find that the current model of a single surface layer (\surd2x\surd2)R45{\deg} reconstruction do...
May 22, 2012
High resolution angle-resolved photoemission measurements are carried out to systematically investigate the effect of cleaving temperature on the electronic structure and Fermi surface of Sr$_2$RuO$_4$. Different from previous reports that high cleaving temperature can suppress surface Fermi surface, we find that the surface Fermi surface remains obvious and strong in Sr$_2$RuO$_4$ cleaved at high temperature, even at room temperature. This indicates that cleaving temperature...
May 22, 2012
High resolution angle-resolved photoemission measurements have been carried out on Sr2RuO4. We observe clearly two sets of Fermi surface sheets near the (\pi,0)-(0,\pi) line which are most likely attributed to the surface and bulk Fermi surface splitting of the \beta band. This is in strong contrast to the nearly null surface and bulk Fermi surface splitting of the \alpha band although both have identical orbital components. Extensive band structure calculations are performed...
August 31, 2000
The electronic structure of Sr2RuO4 is investigated by high angular resolution ARPES at several incident photon energies. We address the controversial issues of the Fermi surface (FS) topology and of the van Hove singularity at the M point, showing that a surface state and the replica of the primary FS due to (sqrt2 x sqrt2) surface reconstruction are responsible for previous conflicting interpretations. The FS thus determined by ARPES is consistent with the de Haas-van Alphe...
March 31, 2011
We present an angle resolved photoemission study of the surface and bulk electronic structure of the single layer ruthenate Sr$_2$RuO$_4$. As the early studies of its electronic structure by photoemission and scanning tunneling microscopy were confronted with a problem of surface reconstruction, surface aging was previously proposed as a possible remedy to access the bulk states. Here we suggest an alternative way by demonstrating that, in the case of Sr$_2$RuO$_4$, circularl...
January 18, 2025
Altermagnets are a novel platform to realize exotic electromagnetic properties distinct from those of conventional ferromagnets and antiferromagnets. We report results of micro-focused angle-resolved photoemission spectroscopy (ARPES) on RuO2, of which altermagnetic nature has been under fierce debate. We have elucidated the band structure of the (100), (110) and (101) surfaces of a bulk single crystal. We found that, irrespective of the surface orientation, the experimental ...
May 11, 2020
The low-energy electronic structure, including the Fermi surface topology, of the itinerant metamagnet Sr$_{4}$Ru$_{3}$O$_{10}$ is investigated for the first time by synchrotron-based angle-resolved photoemission. Well-defined quasiparticle band dispersions with matrix element dependencies on photon energy or photon polarization are presented. Four bands crossing the Fermi-level, giving rise to four Fermi surface sheets are resolved; and their complete topography, effective m...
June 20, 2024
The electronic structure of the topmost layer in Sr2RuO4 in the close vicinity of the Fermi level is investigated by angle-resolved photoemission spectroscopy (ARPES) with a 7-eV laser. We find that the spin-orbit coupling (SOC) predicted as 100 meV by the density functional theory (DFT) calculations is enormously enhanced in a real material up to 250 meV, even more than that of bulk state (200 meV), by the electron-correlation effect increased by the octahedral rotation in t...
August 16, 2012
Motivated by recent angle-resolved photoemission spectroscopy (ARPES) observations of a highly metallic two-dimensional electron gas (2DEG) at the (001) vacuum-cleaved surface of SrTiO3 and the subsequent discussion on the possible role of oxygen vacancies for the appearance of such a state (Ref 1), we analyze by means of density functional theory (DFT) the electronic structure of various oxygen-deficient SrTiO3 surface slabs. We find a significant surface reconstruction afte...