METAL-NONMETAL TRANSITION IN Fe- AND Al-DOPED VO<sub>2</sub>

Brückner, W.; Gerlach, U.; Moldenhauer, W. C.; Brückner, Horst; Thuss, B.; Oppermann, H.; Wolf, E. L.; Storbeck, I.

doi:10.1051/jphyscol:1976410

Cited by 17 publications

(15 citation statements)

References 5 publications

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“…These are the most effective doping elements to reduce the critical temperature as reported from experiments 5,39. In contrast, Fedoping results in greatest volume shrinkage as predicted by our DFT calculations, and the Fe-doping causes the increase in MIT temperature reported from experiments 5,9. In addition, Pan et al suggested that Cr-doping will result in shrinkage of lattice volume, Brown et al observed the increase in transition temperature in Cr-doped VO 2 8,40.…”

contrasting

confidence: 45%

The modulation of metal–insulator transition temperature of vanadium dioxide: a density functional theory study

Sun¹,

Yan²,

Yue³

et al. 2014

J. Mater. Chem. C

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The modulation of metal-insulator transition (MIT) temperature and phase stability of thermochromic materials based on all the transition metal doped VO 2 were systematically studied using density functional theory (DFT) calculations. The free energies, formation enthalpies, and Fermi energies of transition metal doped VO 2 were evaluated from DFT calculations; the cell volumes and bulk moduli were obtained by fitting the free energies to the Birch-Murnaghan equation of states; and the decomposition enthalpies and entropies of the transition metal doped VO 2 were calculated using both experimental data and DFT calculations. Based on these results, the MIT temperature was associated with lattice distortion of VO 2 (M 1 ) upon doping, the expansion of cell volume and the decrease in bangle were associated with the decrease in MIT temperature, and the shrinkage of cell volume and the increase in b-angle were associated with the increase in MIT temperature. And it was also concluded that VO 2 (M 1 ) doped with high valence cations is more stable than those doped with low valence cations.These conclusions are consistent with experimental facts that W-, Mo-, and Re-are the most studied and the most effective dopants for the reduction of MIT temperature, and La-, Hg-, and Ag-doped VO 2 undergoes phase separation. In addition, DFT calculations without spin-polarization were also carried out, and the influence of spin-polarization was evaluated. Finally, scandium was proposed as a potential dopant for VO 2 in view of balanced comprehensive performance.

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contrasting

confidence: 45%

The modulation of metal–insulator transition temperature of vanadium dioxide: a density functional theory study

Sun¹,

Yan²,

Yue³

et al. 2014

J. Mater. Chem. C

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“…Resistance change through the transition was also up to an order of magnitude larger for the doped sample. The lower transition temperature for the Cr-doped sample is noted, since it is known from resistivity measurements on small bulk crystals with a similar composition, 1,2,14 and also from thermal differential analysis of powdered crystals, 15 that Cr substitution of vanadium causes an increase in the transition temperature in comparison with undoped VO 2 . This is also the case for thin films with much higher Cr content.…”

Section: A Thin Film Characterizationmentioning

confidence: 83%

“…%, a morphotropic transition is caused to a different monoclinic phase, designated M 2 . 1,2 This M 2 phase has also been obtained after high-pressure, high-temperature conversion of the M 1 phase, which can stabilize the M 2 phase by generating a defect structure. 3 Application of a relatively small ($0.1 to 1 GPa) uniaxial stress to pure VO 2 M 1 -phase bulk crystals can also induce the M 2 phase.…”

Section: Introductionmentioning

confidence: 99%

Phase transition behavior in microcantilevers coated with M1-phase VO2 and M2-phase VO2:Cr thin films

Rúa¹,

Cabrera²,

Coy³

et al. 2012

Journal of Applied Physics

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Silicon microcantilevers were coated by pulsed laser deposition with vanadium dioxide (VO 2) (monoclinic M 1 phase) and V 1Àx Cr x O 2 with x near 0.024 (monoclinic M 2 phase), and their mechanical characteristics were studied as a function of temperature through the films' insulator-to-metal transition (IMT). The undoped VO 2 films grew with (011) M1 planes parallel to the substrate, while Cr-doped VO 2 films grew oriented with (201) M2 and (201) M2 planes parallel to the substrate. In both cases, the films transformed reversibly through the IMT to the tetragonal (rutile, R) phase, with film (110) R planes oriented parallel to the substrate. The fundamental resonant frequencies of the cantilevers were measured as the temperature was cycled from ambient temperature, through the IMT, and up to 100 C. Very high resonant frequency changes were observed through the transition for both types of samples, with increases during heating of over 11% and over 15% for the cantilevers coated with pure and Cr-doped VO 2 , respectively. From the resonant frequencies measured at room temperature for the bare and coated cantilevers in each case, the effective Young's moduli of the films were determined. The values obtained, assuming bulk densities for the films, are 156 6 7.5 GPa for VO 2 (M 1 phase) and 102 6 3 GPa for Cr-doped VO 2 (M 2 phase). Strong curvature changes during the transition to the R phase were also observed for cantilevers coated with both types of films, but these were significantly higher in the case for the Cr-doped film. Curvature changes for temperature ranges outside the IMT region were small and attributed to differential thermal expansion between film and silicon substrate. From measured cantilever tip displacements in this post-transition range-for the undoped VO 2-coated microcantilevers-a rough estimate of 110 GPa was obtained for the effective Young's modulus for R-phase VO 2. The substantially higher changes in resonant frequency and curvature for V 1Àx Cr x O 2-coated cantilevers suggest that this material may be even more useful than M 1-phase VO 2 for prospective microelectromechanical or optomechanical device applications in which ample frequency tunability-in oscillators or filters-or large displacements-in actuators-within a small temperature range is desirable. Since M 2-phase V 1Àx Cr x O 2 with Cr composition of a few atomic percent retains other desirable properties of VO 2 , such as very high resistivity changes through the IMT and a transition temperature fairly close to ambient temperature, multifunctionality is not impaired and in fact may be enhanced for some applications. V

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“…The doping of low-valent cations such as Fe 3+ , Cr 3+ at low concentration levels would also push the SMPT toward a lower temperature. However, the doping of low-valent cations in high concentration will reverse the SMPT toward a higher temperature [2,11,14,15,16]. Additionally, the doping of Cr 3+ would cause the width of hysteresis loop to be narrower and became more symmetric [17].…”

Section: A N U S C R I P Tmentioning

confidence: 94%

“…According to the literature, the doping of high concentration of iron and nickel elements would increase the phase transition temperature of VO 2 . However, a small amount of pure Fe and Cr elements would decrease the phase transition temperature [2,14,15,16,17,29]. In this study, we aim to examine the synergistic effects on doping Fe, Cr, and Ni elements together and examine their influence on VO 2 films in their phase transition temperature and temperature-dependent hysteresis loop.…”

Section: A N U S C R I P Tmentioning

confidence: 98%

The novel preparation method of high-performance thermochromic vanadium dioxide thin films by thermal oxidation of vanadium-stainless steel co-sputtered films

Yang

Juang

et al. 2015

Vacuum

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METAL-NONMETAL TRANSITION IN Fe- AND Al-DOPED VO₂

Cited by 17 publications

References 5 publications

The modulation of metal–insulator transition temperature of vanadium dioxide: a density functional theory study

The modulation of metal–insulator transition temperature of vanadium dioxide: a density functional theory study

Phase transition behavior in microcantilevers coated with M1-phase VO2 and M2-phase VO2:Cr thin films

The novel preparation method of high-performance thermochromic vanadium dioxide thin films by thermal oxidation of vanadium-stainless steel co-sputtered films

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METAL-NONMETAL TRANSITION IN Fe- AND Al-DOPED VO2

Cited by 17 publications

References 5 publications

The modulation of metal–insulator transition temperature of vanadium dioxide: a density functional theory study

The modulation of metal–insulator transition temperature of vanadium dioxide: a density functional theory study

Phase transition behavior in microcantilevers coated with M1-phase VO2 and M2-phase VO2:Cr thin films

The novel preparation method of high-performance thermochromic vanadium dioxide thin films by thermal oxidation of vanadium-stainless steel co-sputtered films

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METAL-NONMETAL TRANSITION IN Fe- AND Al-DOPED VO₂