Luttinger-liquid-like transport in long InSb nanowires

Long nanowires of degenerate semiconductor InSb in asbestos matrix (wire diameter is around 50 \AA, length 0.1 - 1 mm) were prepared. Electrical conduction of these nanowires is studied over a temperature range 1.5 - 350 K. It is found that a zero-field electrical conduction is a power function of the temperature $G\propto T^\alpha$ with the typical exponent $\alpha \approx 4$. Current-voltage characteristics of such nanowires are found to be nonlinear and at sufficiently low temperatures follows the power law $I\propto V^\beta$. It is shown that the electrical conduction of these nanowires cannot be accounted for in terms of ordinary single-electron theories and exhibits features expected for impure Luttinger liquid. For a simple approximation of impure LL as a pure one broken into drops by weak links, the estimated weak-link density is around $10^3-10^4$ per cm.Comment: 5 pages, 2 figure

Features of superconducting transition in nanocomposite consisting of "insulating matrix (porous alkali-borosilicate glass)" - "granular metallic filler (indium)"

Patterns in temperature and magnetic field behavior of the electrical resistance of nanocomposite consisting of "insulating matrix (7 nm-pore alkali-borosilicate glass)" - "granular metallic filler (indium)" (PG7+In) has been found and analyzed in the vicinity of superconducting transition. Insulating behavior in the electrical resistivity has been observed in a normal state. External magnetic field shifts the transition to lower temperatures and the same time gradually strengths the insulating behavior above the superconducting transitio

Unconventional magnetoresistance in long InSb nanowires

Magnetoresistance in long correlated nanowires of degenerate semiconductor InSb in asbestos matrix (wire diameter of around 5 nm, length 0.1 - 1 mm) is studied over temperature range 2.3 - 300 K. At zero magnetic field the electric conduction $G$ and the current-voltage characteristics of such wires obey the power laws $G\propto T^\alpha$, $I\propto V^\beta$, expected for one-dimensional electron systems. The effect of magnetic field corresponds to a 20% growth of the exponents $\alpha$, $\beta$ at H=10 T. The observed magnetoresistance is caused by the magnetic-field-induced breaking of the spin-charge separation and represents a novel mechanism of magnetoresistance.Comment: To be published in JETP Letters, vol. 77 (2003

Temperature Evolution of Sodium Nitrite Structure in a Restricted Geometry

The NaNO$_{2}$ nanocomposite ferroelectric material in porous glass was studied by neutron diffraction. For the first time the details of the crystal structure including positions and anisotropic thermal parameters were determined for the solid material, embedded in a porous matrix, in ferro- and paraelectric phases. It is demonstrated that in the ferroelectric phase the structure is consistent with bulk data but above transition temperature the giant growth of amplitudes of thermal vibrations is observed, resulting in the formation of a "premelted state". Such a conclusion is in a good agreement with the results of dielectric measurements published earlier.Comment: 4 pages, 4 figure

Structure and properties of confined sodium nitrite

The temperature evolution of the structure of NaNO2 nanocomposite ferroelectric material in a porous glass with 7 nm pores was studied by neutron diffraction in temperature region from room temperature up to the melting, i.e. in the ferro- and paraelectric phases. It is demonstrated that in the ferroelectric phase the structure is consistent with the structure of the bulk, but above the ferroelectric phase transition (and up to ≈ 513 K) a volume premelted state is formed, manifesting itself in a growth of amplitudes of ion thermal vibrations, a steep increase of elementary cell volume and “softening” of lattice. For the first time the temperature dependence of order parameter η for confined sodium nitrite is determined. η (T) follows a power law with T C =425.6± 2.1 K and β= 0.31± 0.04, which is essentially different from that for bulk NaNO2. Our obtained data are in a good agreement with the results of earlier dielectric and neutron diffraction measurements