Determination of the phase coherence length of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>PdCo</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> nanostructures by conductance fluctuation analysis
T. Harada, P. Bredol, H. Inoue, Shun Ito, J. Mannhart, Atsushi Tsukazaki
Abstract
The two-dimensional layered compound $\mathrm{PdCo}{\mathrm{O}}_{2}$ is one of the most conductive oxides, providing an intriguing research arena opened by the long mean free path and the very high mobility of $\ensuremath{\sim}51\phantom{\rule{0.16em}{0ex}}000\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}/\mathrm{V}\phantom{\rule{0.16em}{0ex}}\mathrm{s}$. These properties turn $\mathrm{PdCo}{\mathrm{O}}_{2}$ into a candidate material for nanoscale quantum devices. By exploring universal conductance fluctuations originating in nanoscale $\mathrm{PdCo}{\mathrm{O}}_{2}$ Hall-bar devices, we determined the phase coherence length of electron transport in $c$-axis oriented $\mathrm{PdCo}{\mathrm{O}}_{2}$ thin films to equal \ensuremath{\sim}100 nm. The weak temperature dependence of the measured phase coherence length suggests that defect scattering at twin boundaries in the $\mathrm{PdCo}{\mathrm{O}}_{2}$ thin film governs phase breaking. These results suggest that phase coherent devices can be achieved by realizing the devices smaller than the size of twin domains, via refined microfabrication and suppression of twin boundaries.