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The X-ray diffraction analysis of NbS3 ribbon whiskers has revealed three structural features: (i) a fine-crystalline structure throughout the entire volume with the preferred orientation along the [001] direction perpendicular to the long b axis of the whisker, (ii) the combination of crystalline macroblocks with a length up to 0.5 mm with small crystallites of various orientations, and (iii) the combination of crystalline macroblocks with the left-hand twisting of planes around the b axis with a pitch angle of 1.25° per every 0.2 mm and with the return to the initial orientation in the next block. Structural features (ii) and (iii) of NbS3 whiskers have not yet been observed, and inorganic crystals with such properties are absent to the best of our knowledge. All crystallites have a unit cell with almost right angles and approximately the same lattice constant c (18.130 Å), whereas the lattice constants a and b are noticeably different in a single sample. All crystallites can be referred to phase IV rather than to phase I, as expected. The right angle between the a and c axes can be explained by the twinning of phase I along the c axis. Differences in the lattice constants in macroblocks indicate large stresses in structures. Such stresses near twins (and/or stacking faults) can significantly affect the free electron density and play a key role in the formation of charge density waves in various phases of NbS3. [ABSTRACT FROM AUTHOR]

Three charge density waves (CDWs), two of which are formed above room temperature, are observed in the NbS3 monoclinic phase (NbS3-II). The charge density and mobility in the high-field limit have been determined for each of three CDWs in this work using the synchronization effect of CDWs in high-frequency fields. It has been found that the mobility of each CDW in this limit is approximately equal to the normal-state mobility of quasiparticles condensed in it. Furthermore, correlation has been observed between the temperature dependences of mobilities of CDWs and quasiparticles. The results of this work refresh problems of a mechanism of the limit conductivity of CDWs and of the distribution of CDWs between atomic chains in the unit cell. [ABSTRACT FROM AUTHOR]

A three-dimensional (H, φ, θ, T = 2 K) magnetic phase diagram has been constructed for the first time for the antiferromagnetic metal Er11B12 with an amplitude-modulated magnetic structure exhibiting an electronic instability (dynamic charge stripes). The boundaries determining the shape of the main magnetic phases in the H–φ–θ space are reconstructed from measurements of the magnetoresistance. The role of dynamic charge stripes, which suppress the indirect Ruderman–Kittel–Kasuya–Yoshida exchange between the magnetic moments of the nearest Er3+ ions, and of the single-ion anisotropy in the formation of a complicated multicomponent phase diagram of Er11B12 is discussed. [ABSTRACT FROM AUTHOR]

We show that ultrasound can induce Shapiro steps (SSs) in a charge-density-wave (CDW) state. When ultrasound with frequency ω and a dc voltage are applied, the SSs occur at the current I ∝ n ω with an integer n. Even and odd multiples of SSs are represented by two couplings between the CDW and ultrasound. Although an ac voltage bias with frequency ω induces the SSs at I ∝ n ω , the ultrasound bias enhances the odd multiples more strongly than the even ones. This is the difference between the ultrasound and the ac voltage. Since the SSs cause abrupt peaks in the dV/dI, the extreme changes in the I–V curve will be applied to a very sensitive ultrasound detector. [ABSTRACT FROM AUTHOR]

Understanding the occurrence of charge density wave (CDW) states in quasi-one-dimensional (quasi-1D) transition metal trichalcogenides has attracted substantial research interest. Here, we report the systematic control of hysteretic transitions in quasi-1D TiS3 microribbons by changing the thickness and the cooling rate. Two distinguished resistance hysteresis loops are observed at a high temperature of ∼290 K and a low temperature of ∼60 K, respectively. In addition, two hysteretic transitions exhibit different behaviors under the external perturbations, in which the high temperature hysteretic transition is sensitive to TiS3 microribbons thickness, while the low temperature hysteretic transition is probably related to the CDW state and is robust against external perturbations. Our findings will offer a new frontier of exploration of the hysteretic transitions in the quasi-1D transition metal trichalcogenides. [ABSTRACT FROM AUTHOR]

The layered quasi one-dimensional compound TiS3 is remarkable for its optical properties, especially, photoconductivity. Up to now, photoconductivity in TiS3 was studied only at room temperature. Here, we report photoconductivity, δσ, of the TiS3 whiskers in the temperature range of 5–300 K under irradiation in the near-infrared region. With a temperature decrease from room temperature down to T ∼ 100 K, δσ grows moderately, dominated by the variation of the mobility of the electrons. The estimates based on the values of δσ give the recombination time ∼3–25 μs at 300 K. The results show that above ∼100 K, TiS3 behaves as a semiconductor, where electron–hole pairs are excited across the gap, while the recombination goes through transitions of the excited electrons to a donor level with a long lifetime. Below 60 K, a drop of δσ is likely to reveal a phase transition of electrons into a collective state. Another feature in δσ(T) is seen around 17 K, resembling the temperature variation of the conductivity. This feature indicates a drop in the mobility of the electrons. While the behavior of δσ(T) is consistent with the transition of electrons into a collective state, it is strikingly different from δσ(T) of the known quasi one-dimensional conductors with charge-density waves. [ABSTRACT FROM AUTHOR]