X-ray absorption spectroscopy of layer transition-metal disulfides

Ohno, Youichi; Hirama, Kimiaki; Nakai, S.; Sugiura, Chikara; Okada, S.

doi:10.1103/physrevb.27.3811

Cited by 52 publications

(10 citation statements)

References 34 publications

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“…de Groot et al [31] have analyzed in detail the recorded spectral features of some 3d TM oxides in terms of ligandfield theory. The energy separation between C and C 0 peaks (t 2g -e g splitting) is about 2.0 eV which is approximately equal to that obtained by Fischer [28] (2.1 eV), Ohno et al [29] (2.0 eV), and Sugiura et al [32] (2.0 eV).…”

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confidence: 65%

SulfurK-Edge X-Ray-Absorption Study of the Charge Transfer upon Lithium Intercalation into Titanium Disulfide

et al. 1996

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Sulfur K-edge x-ray-absorption spectra have been recorded for lithium intercalated titanium disulfides Li x TiS 2 . The near-edge features up to 30 eV above threshold are interpreted in the framework of full multiple-scattering theory. We show that the electrons transferred from intercalated lithium atoms are not only located on Ti 3d orbitals, as previously assumed, but also on the S 3p states. For comparison, we present the S p-projected density of states derived from linear muffin-tin-orbital band structure calculations. An overall agreement between measurement and theory is very well achieved.[S0031-9007(96)00962-3] PACS numbers: 78.70.Dm, 71.20.Lp, 72.80.Ga Lamellar transition metal dichalcogenides (TMDC) MX 2 (X S, Se; M Ti, Zr, Hf, V, Nb, Ta, Mo, or W) have been among the first phases considered as a host in intercalation reaction in which a guest species, atom, ion, or molecule can be reversibly inserted into empty spaces of the host structure [1][2][3][4]. Until quite recently, it has been thought that the guest species provides an electron to the transition metal (TM) d orbitals [5][6][7][8]. Such a conclusion is mainly based on a rigid band model. More recent investigations [9,10] tend to show that this model is not adequate to study the intercalation process. Moreover electronic band structure calculations [11] in the extended Hückel approach have shown that, in the case of lithium intercalation into titanium disulfide TiS 2 , there exists a partial electronic transfer of lithium 2s electron to the host structure, on both titanium and sulfur atoms. However, such an approach remains qualitative and is not able to explain the edge shape changes, especially in separating structural and electronic effects. To do so, it is necessary to combine accurate electronic band structure calculations and edge simulations. In this Letter, we present new x-ray absorption spectroscopy (XAS) data and theoretical analyses on the Li intercalated compound TiS 2 that demonstrate the important role of sulfur atoms and provide a correct picture in the intercalation process on TMDC.TiS 2 has been prepared as described in Ref. [12]. Lithium intercalation has been performed by the n-butyl lithium technique at room temperature [13] with the lithium content determined by flame spectroscopy. In order to prevent degradation, samples were handled in glove boxes and transferred to the different systems for analysis via appropriate airtight containers. X-ray appearance near-edge structure (XANES) spectra were recorded using the French synchrotron radiation source at LURE (Orsay). The sulfur K edge was recorded on the Super ACO storage ring with a Si111 two-crystal monochromator, with a 0.4 eV resolution.All the computations of the XANES spectra were carried out using the multiple-scattering CONTINUUM code [14] based on the one-electron full multiple-scattering (MS) theory [15][16][17]. The cluster potential was approximated by a set of spherically averaged muffin-tin (MT) potential, which was built by following the standard Mattheis...

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confidence: 65%

SulfurK-Edge X-Ray-Absorption Study of the Charge Transfer upon Lithium Intercalation into Titanium Disulfide

et al. 1996

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“…A careful consideration shows that the peaks do not represent the density of unoccupied states near the Fermi level and that the doublets are caused by valence fluctuation in the final states as discussed later. The energy band calculations and the XAS spectra of the 1¹ type of LTMDs indicate that the t g -e g splitting is 2.0-2.3 eV for TiS , 1.5 eV for ZrS and 2.0 eV for HfS (29,30). For 1¹-MTe there are no available band calculations which allow the estimation.…”

Section: Xps and Iseels Results Of 1¹-m¹ementioning

confidence: 97%

The Scanning–Tunneling Microscopy, the X-Ray Photoelectron Spectroscopy, the Inner-Shell-Electron Energy-Loss Spectroscopy Studies ofMTe2andM3SiTe6(M=Nb and Ta)

Ohno

1999

Journal of Solid State Chemistry

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“…Another high-temperature synthesis technique did not use LiVS 2 but still resulted in the OCT phase. 58,59 One possibility is that finite temperature plays a role in destabilizing the TP phase since there is evidence that the phonon entropy is greater for the OCT phase. 57 A more recent high-pressure synthesis of VS 2 also yielded the OCT phase.…”

Section: F Possibility Of Realizing Tp Vs2mentioning

confidence: 99%

Electronic correlations in monolayerVS2

Isaacs¹,

Marianetti²

2016

Phys. Rev. B

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The layered transition metal dichalcogenide vanadium disulfide (VS2), which nominally has one electron in the 3d shell, is potent for strong correlation physics and is possibly another realization of an effective one-band model beyond the cuprates. Here monolayer VS2 in both the trigonal prismatic and octahedral phases is investigated using density functional theory plus Hubbard U (DFT+U) calculations. Trigonal prismatic VS2 has an isolated low-energy band that emerges from a confluence of crystal field splitting and direct V-V hopping. Within spin density functional theory, ferromagnetism splits the isolated band of the trigonal prismatic structure, leading to a low-bandgap S = 1/2 ferromagnetic Stoner insulator; the octahedral phase is higher in energy. Including the on-site interaction U increases the band gap, leads to Mott insulating behavior, and for sufficiently high values stabilizes the ferromagnetic octahedral phase. The validity of DFT and DFT+U for these two-dimensional materials with potential for strong electronic correlations is discussed. A clear benchmark is given by examining the experimentally observed charge density wave (CDW) in octahedral VS2, for which DFT grossly overestimates the bond length differences compared to known experiments; the presence of CDWs is also probed for the trigonal prismatic phase. Finally, we investigate why only the octahedral phase has been observed in experiments and discuss the possibility of realizing the trigonal prismatic phase. Our work suggests trigonal prismatic VS2 is a promising candidate for strongly correlated electron physics that, if realized, could be experimentally probed in an unprecedented fashion due to its monolayer nature.

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X-ray absorption spectroscopy of layer transition-metal disulfides

Cited by 52 publications

References 34 publications

SulfurK-Edge X-Ray-Absorption Study of the Charge Transfer upon Lithium Intercalation into Titanium Disulfide

SulfurK-Edge X-Ray-Absorption Study of the Charge Transfer upon Lithium Intercalation into Titanium Disulfide

The Scanning–Tunneling Microscopy, the X-Ray Photoelectron Spectroscopy, the Inner-Shell-Electron Energy-Loss Spectroscopy Studies ofMTe2andM3SiTe6(M=Nb and Ta)

Electronic correlations in monolayerVS2

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