Normal-state conductivity in underdoped La 2 − x Sr x CuO 4 thin films: Search for nonlinear effects related to collective stripe motion
Normal-state conductivity in underdoped La 2 − x Sr x CuO 4 thin films: Search for nonlinear effects related to collective stripe motion
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DOI：
10.1103/physrevb.68.094506
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发表时间：
2003-08
影响因子：
3.7
通讯作者：
A. Lavrov;I. Tsukada;Y. Ando
中科院分区：
文献类型：
--
作者：
A. Lavrov;I. Tsukada;Y. Ando
We report a detailed study of the electric-field dependence of the normal-state conductivity in ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}$ thin films for two concentrations of doped holes, $x=0.01$ and 0.06, where formation of diagonal and vertical charged stripes was recently suggested. In order to elucidate whether high electric fields are capable of depinning the charged stripes and inducing their collective motion, we have measured current-voltage characteristics for various orientations of the electric field with respect to the crystallographic axes. However, even for the highest possible fields $(\ensuremath{\sim}1000\mathrm{V}/\mathrm{c}\mathrm{m}$ for $x=0.01$ and $\ensuremath{\sim}300\mathrm{V}/\mathrm{c}\mathrm{m}$ for $x=0.06)$ we observed no nonlinear conductivity features except for those related to the conventional Joule heating of the films. Our analysis indicates that Joule heating, rather than collective electron motion, may also be responsible for the nonlinear conductivity observed in some other two-dimensional transition-metal oxides as well. We discuss that a possible reason why moderate electric fields fail to induce a collective stripe motion in layered oxides is that fairly flexible and compressible charged stripes can adjust themselves to the crystal lattice and individual impurities, which makes their pinning much stronger than in the case of conventional rigid charge-density waves.
We report a detailed study of the electric-field dependence of the normal-state conductivity in ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}$ thin films for two concentrations of doped holes, $x=0.01$ and 0.06, where formation of diagonal and vertical charged stripes was recently suggested. In order to elucidate whether high electric fields are capable of depinning the charged stripes and inducing their collective motion, we have measured current-voltage characteristics for various orientations of the electric field with respect to the crystallographic axes. However, even for the highest possible fields $(\ensuremath{\sim}1000\mathrm{V}/\mathrm{c}\mathrm{m}$ for $x=0.01$ and $\ensuremath{\sim}300\mathrm{V}/\mathrm{c}\mathrm{m}$ for $x=0.06)$ we observed no nonlinear conductivity features except for those related to the conventional Joule heating of the films. Our analysis indicates that Joule heating, rather than collective electron motion, may also be responsible for the nonlinear conductivity observed in some other two-dimensional transition-metal oxides as well. We discuss that a possible reason why moderate electric fields fail to induce a collective stripe motion in layered oxides is that fairly flexible and compressible charged stripes can adjust themselves to the crystal lattice and individual impurities, which makes their pinning much stronger than in the case of conventional rigid charge-density waves.