Nonlocal transport in the charge density waves of $o{\text{-TaS}}_3$

We studied the nonlocal transport of a quasi-one-dimensional conductor $o{\text{-TaS}}_3$. Electric transport phenomena in charge density waves include the thermally excited quasiparticles and collective motion of charge density waves (CDWs). In spite of its long-range correlation, the collective motion of a CDW does not extend far beyond the electrodes, where phase slippage breaks the correlation. We found that nonlocal voltages appeared in the CDW of $o{\text{-TaS}}_3$, both below and above the threshold field for CDW sliding. The temperature dependence of the nonlocal voltage suggests that the observed nonlocal voltage originates from the CDW even below the threshold field. Moreover, our observation of nonlocal voltages in both the pinned and sliding states reveals the existence of a carrier with long-range correlation, in addition to sliding CDWs and thermally excited quasiparticles.

Figure 1

(Color online) Configurations for the measurements: (a) normal configuration, (b) transposed configuration, and (c) nonlocal configuration. The polarity of the voltmeter in the nonlocal configuration provides a positive value when the spreading resistance is dominant.

Figure 2

Temperature dependence of sample resistance. Broken line is an Arrhenius fit $R\propto \text{exp}\left(T/T_0\right)$, with $T_0=790\text{K}$.

Figure 3

(Color online) Current-voltage characteristics at 130 K for the normal, transposed, and nonlocal configurations, denoted by black, red (gray), and green (light gray) curves, respectively.

Figure 4

(Color online) (a) Temperature evolution of the nonlocal voltages at 130, 180, and 250 K. Polarity inversion was seen below and above the Peierls transition, 220 K. (b) Schematic diagram of flow lines to provide spreading resistance. (c) Possible correlation between current and voltage probes via dislocation lattice. (d) Correlation of sliding CDW is Fig. 1 exceeded over current probes.