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The charge response of a charge-ordered state in the organic conductor $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}(\mathrm{BEDT}\mathrm{\text{\ensuremath{-}}}\mathrm{TTF}{)}_{2}{\mathrm{I}}_{3}$ is characterized by dc resistivity, dielectric and optical spectroscopy in different crystallographic directions within the two-dimensional conduction layer. Two dielectric modes are detected. The large mode is related to the phasonlike excitation of the $2{k}_{F}$ bond-charge density wave which forms in the $ab$ plane. The small dielectric mode is associated with the motion of domain-wall pairs along the $a$ and $b$ axes between two types of domains which are created due to inversion symmetry breaking.

The charge response of a charge-ordered state in the organic conductor α-(BEDT-TTF)2I3 is characterized by dc resistivity, dielectric and optical spectroscopy in different crystallographic directions within the two-dimensional conduction layer. Two dielectric modes are detected. The large mode is related to the phasonlike excitation of the 2k(F) bond-charge density wave which forms in the ab plane. The small dielectric mode is associated with the motion of domain-wall pairs along the a and b axes between two types of domains which are created due to inversion symmetry breaking.

We have investigated the dimensionality and origin of the magnetotransport properties of LaAlO3 films epitaxially grown on TiO2-terminated SrTiO3(001) substrates. High-mobility conduction is observed at low deposition oxygen pressures (PO2

We have investigated the dimensionality and origin of the magnetotransport properties of LaAlO3 films epitaxially grown on TiO2-terminated SrTiO3(001) substrates. High-mobility conduction is observed at low deposition oxygen pressures (P(O2)10(-5) mbar) and has a three-dimensional character. However, at higher P(O2) the conduction is dramatically suppressed and nonmetallic behavior appears. Experimental data strongly support an interpretation of these properties based on the creation of oxygen vacancies in the SrTiO3 substrates during the growth of the LaAlO3 layer. When grown on SrTiO3 substrates at low P(O2), other oxides generate the same high mobility as LaAlO3 films. This opens interesting prospects for all-oxide electronics.

The charge response in the spin chain and/or ladder compound ${\mathrm{S}\mathrm{r}}_{14\ensuremath{-}x}{\mathrm{C}\mathrm{a}}_{x}{\mathrm{C}\mathrm{u}}_{24}{\mathrm{O}}_{41}$ is characterized by dc resistivity, low-frequency dielectric spectroscopy and optical spectroscopy. We identify a phase transition below which a charge-density wave (CDW) develops in the ladder arrays. Calcium doping suppresses this phase with the transition temperature decreasing from 210 K for $x=0$ to 10 K for $x=9$, and the CDW gap from 130 meV down to 3 meV, respectively. This suppression is due to the worsened nesting originating from the increase of the interladder tight-binding hopping integrals, as well as from disorder introduced at the Sr sites. These results altogether speak in favor of two-dimensional superconductivity under pressure.

The low temperature phase (LTP) of alpha-(BEDT-TTF)2KHg(SCN)(4) salt is known for its surprising angular dependent magnetoresistance (ADMR), which has been studied intensively in the last decade. However, the nature of the LTP has not been understood until now. Here we analyze theoretically ADMR in unconventional (or nodal) charge-density wave (UCDW). In magnetic field the quasiparticle spectrum in UCDW is quantized, which gives rise to spectacular ADMR. The present model accounts for many striking features of ADMR data in alpha-(BEDT-TTF)2KHg(SCN)(4).

The charge response in the spin chain and/or ladder compound Sr14-xCaxCu24O41 is characterized by dc resistivity, low-frequency dielectric spectroscopy and optical spectroscopy. We identify a phase transition below which a charge-density wave (CDW) develops in the ladder arrays. Calcium doping suppresses this phase with the transition temperature decreasing from 210 K for x=0 to 10 K for x=9, and the CDW gap from 130 meV down to 3 meV, respectively. This suppression is due to the worsened nesting originating from the increase of the interladder tight-binding hopping integrals, as well as from disorder introduced at the Sr sites. These results altogether speak in favor of two-dimensional superconductivity under pressure.

Magnetic and M\"ossbauer measurements on a $\mathrm{Au}$-19-at.%-Fe alloy are reported. After ferromagnetic ordering at ${T}_{c}\ensuremath{\cong}170$ K, spin-glass-like transverse ordering sets in below $T\ensuremath{\cong}60$ K; strong irreversibility in the magnetization process only occurs below $T\ensuremath{\cong}15$ K. This behavior is consistent with the predictions of a Heisenberg mean-field model, in which the transverse ordering transition is distinct from a crossover to strong irreversibility.