Anisotropy-induced crossover from Drude conductivity to charge-density-wave excitations in a stripe-type charge-ordered manganite

• Published in: Physical review. B, Condensed matter and materials physics Vol. 87; no. 22
• Main Authors: Rana, Rakesh, Pandey, Parul, Rana, D. S., Mavani, K. R., Kawayama, I., Murakami, H., Tonouchi, M.
• Format: Journal Article
• Language: English
• Published: 24-06-2013
• Subjects: Carbon monoxide; Charge; Condensed matter; Crossovers; Dynamical systems; Dynamics; Excitation; Manganites
• ISSN: 1098-0121; 1550-235X
• DOI: 10.1103/PhysRevB.87.224421

The half-doped Pr sub(0.05) Sr sub(0.5) MnO sub(3) (PSMO) manganite represents a unique stripe type of charge orbital order that induces transport and magnetic anisotropy. Low-energy charge dynamics in PSMO (110) epitaxial film were investigated along and across two dissimilar in-plane orthogonal axes, [1-10] and [001], by recording the complex refractive index in the energy range of 1-7 meV. We report a novel observation of a gradual crossover from Drude-like metallic conductivity to charge-density-wave (CDW)-like collective excitations as the polarized terahertz excitation field is swept across the orthogonal in-plane axes. This is a rare manifestation of a CDW mode in a highly conducting stripe-type charge-ordered (CO) system, which is fundamentally different from the CDW modes of checkerboard CO. Interestingly, the contrasting charge dynamics along orthogonal in-plane axes form an intrinsic electronic switch, apparently a consequence of the unique CO of PSMO.