Structural and vibrational properties of corundum-type In₂O₃nanocrystals under compression

Abstract

This work reports the structural and vibrational properties of nanocrystals of corundum-type InO (rh-InO) at high pressures by using angle-dispersive x-ray diffraction and Raman scattering measurements up to 30 GPa. The equation of state and the pressure dependence of the Raman-active modes of the corundum phase in nanocrystals are in good agreement with previous studies on bulk material and theoretical simulations on bulk rh-InO. Nanocrystalline rh-InO showed stability under compression at least up to 20 GPa, unlike bulk rh-InO which gradually transforms to the orthorhombic Pbca (RhO-III-type) structure above 12-14 GPa. The different stability range found in nanocrystalline and bulk corundum-type InO is discussed.

Pressure-Induced Phase Transitions in Sesquioxides

“…This result is controversial since other studies using HP-XRD and HP-RS measurements did not clearly observe this PT up to 30 GPa [100,101] nanoparticles (10-30 nm) up to 30 GPa using XRD and RS measurements [109]. XRD measurements did not show any PT up to 30 GPa, but RS measurements showed peaks of the o3-In 2 O 3 phase above 20 GPa [109]. One reason for this discrepancy was attributed to the sensitivity of RS measurements to local structural changes, which is responsible for the observation of PTs at lower pressures in RS compared to XRD measurements [109].…”

“…Some HP-XRD studies of both bulk and nanoparticle samples claimed that the c-In 2 O 3 → rh-In 2 O 3 PT occurs at RT when the sample is exposed to pressures between 12 and 25 GPa [103,104]. This result is controversial since other studies using HP-XRD and HP-RS measurements did not clearly observe this PT up to 30 GPa [100,101] nanoparticles (10-30 nm) up to 30 GPa using XRD and RS measurements [109]. XRD measurements did not show any PT up to 30 GPa, but RS measurements showed peaks of the o3-In 2 O 3 phase above 20 GPa [109].…”

“…HP studies in group-13-SOs have been conducted on the five compounds. Al 2 O 3 , also known as alumina, is by far the most studied compound [85][86][87][88][89][90][91][92][93][94][95][96][97][98][99], followed by In 2 O 3 [100][101][102][103][104][105][106][107][108][109], Ga 2 O 3 [107,[110][111][112][113][114], and B 2 O 3 [115][116][117][118][119][120][121]. Finally, Tl 2 O 3 has been the least studied compound [122].…”

Quantum Crystallography: Current Developments and Future Perspectives

“…By integration over bonds and lone pairs, properties (e.g. [206] It is important to note that the ELF and ELI require the first-order density matrix, so that quantum crystallography developments also hold great potential for these analyses. This analysis allows for example to rationalize the formation of channels in MOFs,c lathrates or molecular crystals.…”

Ordinary dielectric function of corundumlike α−Ga2O3 from 40 meV to 20 eV

“…Moreover, several metal oxides that crystallize in the corundumlike structure are also available as bulk, e.g., Cr 2 O 3 [22], opening the opportunity to investigate alternative substrates for α-Ga 2 O 3 . The possibility to create alloys [23] with α-In 2 O 3 [24][25][26][27][28] or α-Al 2 O 3 is a further invaluable advantage. Consequently, the growth of phase pure alloys [29] and advanced functional heterostructures is possible [30].…”