Electronic structure of titanium monoxide

Bartkowski, S.; Neumann, M.; Kurmaev, E.Z.; Федоренко, В. В.; Shamin, S. N.; Cherkashenko, V. M.; Nemnonov, S. N.; Winiarski, A.; Rubie, D. C.

doi:10.1103/physrevb.56.10656

Cited by 114 publications

(77 citation statements)

References 45 publications

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“…In agreement with previous studies we assign the feature located at 7.4 eV to O 2p-Ti 3d hybridized states, while the 5.5 eV feature has mainly O 2p character [11]. One can see, that the ratio of the two peaks located at 7.4 and 5.5 eV is found to be very similar to that of TiO 2 [5]. C 2s-states are fixed at E = 14.5 eV and are seen mainly in the spectrum of untreated cp-Ti where the contribution of carbon contamination is the highest (see Figures 1 and 5).…”

Section: Resultssupporting

confidence: 77%

“…According to XPS measurements of high-energy resolved Ti 2p 3/2, 1/2 spectra (Figure 4), the Ti 2p 3/2 and Ti 2p 1/2 peaks are located at 459.2 eV and 464.9 eV both before and after acid treatment and can be attributed to Ti 4+ [5]. No Ti 3+ shoulder at lower binding energy on the Ti 2p 3/2 peak is detected, suggesting that all samples have a stoichiometric TiO 2 surface.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Surface Characterization of Titanium Implants Treated in Hydrofluoric Acid

Korotin¹,

Bartkowski²,

Kurmaev³

et al. 2012

JBNB

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The results of XPS measurements of commercially pure titanium (cp-Ti) before and after chemical treatment are presented. We have measured XPS spectra of core levels (Ti 2p, O 1s, C 1s, F 1s) and valence bands of coarse-grained cp-Ti before and after standard acid treatment accepted in dentistry (in 1% HF and 40% HF for 1 min). It is found, that acid treatment of cp-Ti reduces the content of hydrocarbons increasing the surface energy and bio-compatibility of Ti-implants. On the other hand, it is fixed that oxygen concentration on the surface of the acid treated cp-Ti is much higher than for the untreated sample, because the acid treatment removes the contaminated surface layers, increases their reactivity, provides a better passivation and formation of thick protecting TiO 2 layer.

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Surface Characterization of Titanium Implants Treated in Hydrofluoric Acid

Korotin¹,

Bartkowski²,

Kurmaev³

et al. 2012

JBNB

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“…The bandwidth of the occupied states is reduced by about 1 eV with the appearance of vacan cies in the basic structure. This is agrees with the experimental data [15]. The low energy part of the band of occupied states mainly includes 2p states of oxygen, and the high energy part includes 3d states of titanium.…”

Section: Role Of Structural Vacanciessupporting

confidence: 82%

Role of structural vacancies in the stabilization of the basic B1 structure in nonstoichiometric titanium monoxide TiO y

Kostenko

Lukoyanov

Жуков

et al. 2013

Bull. Russ. Acad. Sci. Phys.

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Titanium monoxide TiO y is one of the few nonsto ichiometric compounds with a high concentration of structural vacancies in both sublattices. Their percent age can be up to 32 at % [1][2][3][4]. In the case of an equi atomic composition, the amount of vacancies is about 14-15 at % in each sublattice [3,4]. When the compo sition deviates from stoichiometric, the concentration of vacant sites increases in one sublattice and decreases in another [1]. The high content of vacan cies results in a wide homogeneity of titanium monox ide, which is in the range of y = 0.7-1.25 [3].Three stoichiometric crystal modifications of tita nium monoxide composition are known. They all have the basic B1 structure, but they differ from each other by the presence of vacancies and their specific loca tion. One can obtain a phase without structural vacan cies by annealing at high pressures [5]. At low pres sures, the thermodynamic equilibrium phases are those with vacancies. Vacancies may be located over sites of the basic В1 structure either randomly or in an ordered manner. The disordered state is thermody namically stable at temperatures above 1300 K, but it can be obtained at room temperature by quenching [3,4]. Since the vacancies are chaotically located, the X ray diffraction patterns of disordered samples exhibit only characteristic of the cubic B1 structure. The vacancies are ordered during slow annealing from the temperature of the order-disorder phase transi tion; the crystal symmetry is lowered to monoclinic, so a Ti 5 О 5 phase is formed [3,4].Thus, the presence of vacancies and their ordering is energetically favorable for titanium monoxide. However, the role of vacancies in stabilization of the basic B1 structure is poorly understood. There are many theoretical studies dedicated to this problem [6][7][8][9][10][11][12][13]. For example, the electron structure of the TiO and Ti 5 O 5 phase and disordered stoichiometric TiO 1.0 phase have been calculated in [12]. However, the ordered and disordered phases have been studied by various methods, which has made it impossible to compare their total energies adequately. In [13], only TiO and Ti 5 O 5 were considered. It was shown that a crucial role in stabilizing the ordered phase is played by oxygen vacancies; however, the reasons for the sta bility of the disordered state have not been considered. Thus, what the role of metal and nonmetal vacancies in disordered and ordered phase are remains an open question. This paper is aimed at determining the contribu tion of titanium and oxygen vacancies in the stabiliza tion of the basic B1 structure and to investigate the sta bility of crystal titanium monoxide modifications. To do this, we calculated the electron structures and total energies of the three phases: vacancy free cubic TiO, vacancy ordered monoclinic Ti 5 O 5 , and vacancy dis ordered cubic TiO y ; analyzed the features of the chem ical bond; and found the stablest crystal modification.The electron structure was calculated with the den sity functional theory and account f...

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“…[4][5][6][7] The electrical, optical, magnetic, and structural properties of bulk TiO have been widely investigated. [8][9][10][11][12][13][14][15][16][17] Especially, the superconductivity in TiO bulk materials was discovered in the early 1965s by Hulm et al 18 They reported that, for the bulk TiO with NaCl structure, its superconducting transition temperature T c increases from 0.2 to 1.0 K with oxygen content increases from 0.9 to 1.1, but is below 0.08 K outside this range. 19 Further investigations showed that highpressure annealing increases the oxygen content and lattice constant of cubic TiO bulk, and its superconducting transition temperature increases linearly with oxygen content to a maximum of 2.0 K. 4,7 However, the intrinsic superconducting properties of TiO, such as the lower and upper critical fields, superconducting coherence length and so on, are not clear yet, due to the difficulty in obtaining single crystals or epitaxial films.…”

Section: Introductionmentioning

confidence: 99%

Enhanced superconductivity in TiO epitaxial thin films

et al. 2017

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Titanium oxides have many fascinating optical and electrical properties, such as the superconductivity at 2 K in cubic titanium monoxide (TiO) polycrystalline bulk. However, the lack of TiO single crystals or epitaxial films has prevented systematic investigations on its superconductivity. Here, we report the basic superconductivity characterizations of cubic TiO films epitaxially grown on (0001)-oriented α-Al 2 O 3 substrates. The magnetic and electronic transport measurements confirmed that TiO is a type-II superconductor and the recorded high T c is about 7.4 K. The lower critical field (H c1 ) at 1.9 K, the extrapolated upper critical field H c2 (0), and coherence length are about 18 Oe, 13.7 T, and 4.9 nm, respectively. With increasing pressure, the value of T c shifts to lower temperature while the normal state resistivity increases. Our results on the superconducting TiO films confirm the strategy to achieve higher T c in the epitaxial films, which may be helpful for finding more superconducting materials in various related systems.

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Electronic structure of titanium monoxide

Cited by 114 publications

References 45 publications

Surface Characterization of Titanium Implants Treated in Hydrofluoric Acid

Surface Characterization of Titanium Implants Treated in Hydrofluoric Acid

Role of structural vacancies in the stabilization of the basic B1 structure in nonstoichiometric titanium monoxide TiO y

Enhanced superconductivity in TiO epitaxial thin films

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