Nonlinear conductivity of NbS<Subscript>3</Subscript> in a high-pressure metallic phase

The temperature dependence of the conductivity of a quasi-one-dimensional NbS₃ conductor after its transition to a metallic state has been measured at a pressure higher than 6 GPa. A region of an increased differential resistance rapidly disappearing above 40 K has been observed in low electric fields ≤4 V/cm. A narrow dip against the background of this region appears in the resistance below 3.7 K.     

Energy gap revealed by low-temperature scanning-tunnelling spectroscopy of the Si(111)-7×7 surface in illuminated slightly doped crystals

Physical properties of the Si(111)-7×7 surface of low-doped n- and p-type Si samples are studied in the liquid helium temperature region by scanning-tunnelling microscopy and spectroscopy. Conduction required for the study is provided by illumination of the surface. Application of illumination completely removes the band bending near the surface and restores the initial population of the surface states. Our results indicate the existence of the energy gap 2Δ?=?40?±?10?meV in the intrinsically populated Si(111)-7×7 surface.     

Nonlinear low-temperature magnetization of the quasi-one-dimensional charge-density-wave conductor K0.3 MoO3

A study is made of the temperature and field dependences of the anisotropic magnetization of a quasi-one-dimensional charge-density-wave conductor — the blue bronze K_0.3 MoO₃. Nonlinearity of the magnetization curves is observed at temperatures below 100 K. The temperature and field dependences of the magnetic moment show the effect to be of a collective nature. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 4, 281–286 (25 August 1998)     

Photoconduction and photocontrolled collective effects in the Peierls conductor TaS<Subscript>3</Subscript>

Light illumination of thin crystals of CDW conductor TaS₃ is found to result in dramatic changes of both linear (G) and nonlinear conduction. The increase of G is accompanied by suppression of the collective conduction, growth of the threshold field E _T , and appearance of the switching and hysteretic behavior in the nonlinear conduction. The effects in the nonlinear conduction are associated with increase of CDW elasticity due to illumination that leads, in particular, to the appearance of a relation E _T ∝ G^1/3 expected for the one-dimensional pinning.     

Freezing of low energy excitations in charge density wave glasses

Thermally stimulated discharge current measurements were performed to study slow relaxation processes in two canonical charge density wave systems K(0.3)MoO(3) and o-TaS(3). Two relaxation processes were observed and characterized in each system, corroborating the results of dielectric spectroscopy. Our results are consistent with the scenario of the glass transition on the charge density wave superstructure level. In particular, the results directly prove the previously proposed criterion of charge density wave freezing based on the interplay of charge density wave pinning by impurities and screening by free carriers. In addition, we obtained new information on distribution of relaxation parameters, as well as on nonlinear dielectric response both below and above the threshold field for charge density wave sliding.     

Growth,crystal structure and transport properties of quasi one-dimensional conductors NbS3

We report synthesis of quasi-one-dimensional conductor NbS₃, TEM studies and transport properties of the prepared samples. The grown NbS₃ whiskers are Peierls conductors known as phase II with the transitions at T_P1=365 K and T_P2=150 K. CDW1 is stable and not so sensitive to growth conditions. It can slide and be synchronized by the external microwave irradiation up to 16 GHz. CDW2 strongly depends on growth conditions. Nevertheless, it also shows sliding and synchronization.     

One-dimensionality effects in quasi-one-dimensional conductors

The electrophysical properties of quasi-one-dimensional conductors with a charge-density wave change qualitatively upon a decrease in their transverse sizes. The temperature and electric-field dependences of the conductivities of thin samples are governed by the laws expected for one-dimensional electron systems. The results of studying these effects and the present-day knowledge of their origin are presented.