Photoemission study of the electronic structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CrCl</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">RuCl</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Pollini, I.

doi:10.1103/physrevb.50.2095

Cited by 57 publications

(40 citation statements)

References 51 publications

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“…This reflects the different orbital character of the underlying states, which causes a different dependence of the photoionization cross section on photon energy. By comparison with tabulated values peak 1 and 2 can be assigned to Cl 3p and peak 3 to Ru 4d states [21] in agreement with previous results [12]. However, an important difference to the earlier studies is that we observe a larger gap.…”

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confidence: 90%

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JeffDescription of the Honeycomb Mott Insulatorα−RuCl3

Koitzsch¹,

Habenicht²,

Muller³

et al. 2016

Phys. Rev. Lett.

108

107

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Novel ground states might be realized in honeycomb lattices with strong spin-orbit coupling. Here we study the electronic structure of α-RuCl3, in which the Ru ions are in a d 5 configuration and form a honeycomb lattice, by angle-resolved photoemission, x-ray photoemission and electron energy loss spectroscopy supported by density functional theory and multiplet calculations. We find that α-RuCl3 is a Mott insulator with significant spin-orbit coupling, whose low energy electronic structure is naturally mapped onto J ef f states. This makes α-RuCl3 a promising candidate for the realization of Kitaev physics. Relevant electronic parameters such as the Hubbard energy U, the crystal field splitting 10Dq and the charge transfer energy ∆ are evaluated. Furthermore, we observe significant Cl photodesorption with time, which must be taken into account when interpreting photoemission and other surface sensitive experiments.

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confidence: 90%

“…RuCl 3 has been known for a long time and is even of some importance as a chemical [10]. Its electronic structure has been repeatedly investigated over the years by optical spectroscopy and photoemission [11][12][13]. The picture of a Mott-insulating state was proposed where the Ru 4d bands are situated close to E F but show little dispersion [13].…”

mentioning

confidence: 99%

JeffDescription of the Honeycomb Mott Insulatorα−RuCl3

Koitzsch¹,

Habenicht²,

Muller³

et al. 2016

Phys. Rev. Lett.

108

107

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“…Models describing these phenomena involve double exchange, Jahn-Teller ͑JT͒, superexchange, and Coulomb on-site ͑Hubbard U͒ interactions that yield effective low-energy Hamiltonians, which predict different types of quasiparticle excitations, such as spin excitations, lattice polarons, spin polarons, or orbitons. 3,4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, the effective Hamiltonians used to describe the manganites typically ignore the oxygen p bands and consider only an effective manganese d band. It is also generally assumed that the high-energy degrees of freedom can be neglected by a "down folding" of the large number of bands into a single effective band.…”

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confidence: 99%

Metal-insulator transition in manganites: Changes in optical conductivity up to 22 eV

et al. 2008

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The electronic response of doped manganites at the transition from the paramagnetic insulating to the ferromagnetic metallic state in La 1−x Ca x MnO 3 for x = 0.3 and 0.2 was investigated by dc conductivity, ellipsometry, and vacuum ultraviolet reflectance for energies between 0 and 22 eV. A stabilized Kramers-Kronig transformation yields the optical conductivity and reveals changes in the optical spectral weight up to 22 eV at the metal-to-insulator transition. In the observed energy range, the spectral weight is conserved within 0.3%. The redistribution of spectral weight in this surprisingly broad energy range has important ramifications for the effective low-energy physics. We discuss the importance of the charge-transfer, Coulomb on-site, Jahn-Teller, and long-range Coulomb screening effects to the electronic structure. Among strongly correlated materials, the manganites exhibit a wealth of novel properties. For example, some hexagonal insulating materials exhibit multiferroic behavior and the cubic doped manganites show charge ordering and the colossal magnetoresistance ͑CMR͒ effect.1,2 It is clear that the two key ingredients responsible for these diverse phenomena are, first, the high geometrical and spin frustration and, second, the large number of competing interactions, the most important of which are the electron-electron and electron-phonon interactions. 1,[3][4][5][6][7][8][9] There is a deep disagreement as to which of these interactions is the primary driving force behind either the insulating phase of the manganites or the metal-to-insulator transition in the doped manganites. Models describing these phenomena involve double exchange, Jahn-Teller ͑JT͒, superexchange, and Coulomb on-site ͑Hubbard U͒ interactions that yield effective low-energy Hamiltonians, which predict different types of quasiparticle excitations, such as spin excitations, lattice polarons, spin polarons, or orbitons. 3,4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, the effective Hamiltonians used to describe the manganites typically ignore the oxygen p bands and consider only an effective manganese d band. It is also generally assumed that the high-energy degrees of freedom can be neglected by a "down folding" of the large number of bands into a single effective band. This implies that there is no redistribution of electronic states between low-energy and high-energy degrees of freedom. On the other hand, if one considers the importance of local interactions and hybridization in correlated materials, one would expect quite pronounced effects at higher energies that are connected to charge-transfer or Mott-Hubbard physics. 15,[22][23][24] Thus, the important test for the effective low-energy picture is to study whether one finds strong exchanges of spectral weight between low and high energies.Therefore, it is crucial to test the complex nature of the band structure explicitly. The most direct experiment is to measure the dielectric response of a material as a function of temperature and doping. Unfort...

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“…The crystal thicknesses of these mica-like platelets of average area 0.8 cm 2 range from 10 to 50 mm. The identity of CrBr 3 crystrals was established by means of high energy electron Bragg diffraction patterns and stoichiometry by means of chemical analysis, as it was made earlier in CrCl 3 [23]. The low-temperature crystalline structure of CrCl 3 (T < 238 K) and that of CrBr 3 (T < 450 K) is like the BiI 3 layer structure (space group C 3i .…”

Section: Methodsmentioning

confidence: 99%

“…The insulating nature of CrX 3 seems mainly due to the correlation between 3d electrons, with a value of the Coulomb energy parameter U 3:0±3.5 eV. In other words, layered Cr halides, with a 15±20% covalency, and a CT parameter of D 5:5±6.5 eV, do not show a value of the hybridisation parameter T 1:5 eV as large as the early TM oxides T 3:5±4.0 eV, and thus the Cr main photoemission band has been interpreted within a local-ion excitation model [21] and described by ligand field poorly screened final states [22,23]. X-ray photoelectron spectra (XPS) of the Cr2p and Cr3p electrons in CrX 3 have been reported for evaporated samples [24,25] and these results have been compared to theoretical spectra calculated on the basis of the ligand field (LF) theory [26].…”

Section: Introductionmentioning

confidence: 99%