Influence of Structural Disorder on Hollandites A(x)Ru4O8 (A(+) = K, Rb, Rb(1-x)Na(x))

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Structural disorder significantly influences the electrical properties of correlated materials.
• Hollandites, a class of tunnel-structured oxides, are of interest for their unique electronic behaviors.

Purpose of the Study:

• To investigate the relationship between structural disorder and electrical resistivity in hollandites A(x)Ru4O8.
• To quantify average and local disorder using neutron scattering.
• To correlate disorder levels with temperature-dependent resistivity and magnetic properties.

Main Methods:

• Neutron total scattering techniques were employed to analyze hollandite samples.
• Atomic displacement parameters were used to quantify local disorder.
• Electrical resistivity and Pauli paramagnetism were measured across a temperature range.

Main Results:

• Samples with A(+) = Rb and Rb(1-x)Na(x) exhibited greater local disorder compared to K(x)Ru4O8.
• Increased local disorder correlated with a weakened temperature dependence of resistivity.
• All hollandite samples displayed anisotropic resistivity, with metallic conductivity at low temperatures.
• Pauli paramagnetic behavior was observed across the measured temperature range for all samples.

Conclusions:

• Local structural disorder plays a crucial role in modulating the electrical properties of hollandites.
• The degree of disorder influences the temperature dependence of resistivity.
• Hollandites exhibit metallic conductivity and Pauli paramagnetism, consistent with their electronic structure.