A Rutile Chevron Modulation in Delafossite-Like Ga3-xIn3TixO9+x/2

作者：Rickert Karl; Boullay Philippe; Malo Sylvie; Caignaert Vincent; Poeppelmeier Kenneth R^*

来源：Inorganic Chemistry, 2016, 55(9): 4403-4409.

DOI：10.1021/acs.inorgchem.6b00147

The structure solution of the modulated, delafossite-related, orthorhombic Ga3-xIn3TixO9+x/2 for x = 1.5 is reported here in conjunction with a model describing the modulation as a function of x for the entire system. Previously reported structures in the related A(3-x)In(3)Ti(x)O(9+x/2) (A = Al, Cr, or Fe) systems use X-ray diffraction to determine that the anion lattice is the source of modulation. Neutron diffraction, with its enhanced sensitivity to light atoms, offers a route to solving the modulation and is used here, in combination with precession electron diffraction tomography (PEDT), to solve the structure of Ga1.5In3Ti1.5O9.75. We construct a model that describes the anion modulation through the formation of rutile chevrons as a function of x. This model accommodates the orthorhombic phase (1.5 <= x <= 2.1) in the Ga3-xIn3TixO9+x/2 system, which transitions to a biphasic mixture (2.2 <= x <= 2.3) with a monoclinic, delafossite-related phase (2.4 <= x <= 2.5). The optical band gaps of this system are determined, and are stable at similar to 3.4 eV before a similar to 0.4 eV decrease between x = 1.9 and 2.0. After this decrease, stability resumes at similar to 3.0 eV. Resistance to oxidation and reduction is also presented.

• 出版日期2016-5-2
• 单位西北大学