相关论文: Optical Evidence for Mixed Phase Behavior in Manga…

We investigated the temperature-dependent optical conductivity of NaV2O5 in the energy range 4 meV-4 eV. The intensities and the polarization dependence of the detected electronic excitations give a direct indication for a broken-parity…

Thin films of the charge-ordered (CO) compound Pr$_{0.5}$Ca$_{0.5}$MnO$_{3}$ have been deposited onto (100)-oriented SrTiO$_{3}$ substrates using the Pulsed Laser Deposition technique. Magnetization and transport properties are measured…

The electronic response of doped manganites at the transition from the paramagnetic insulating to the ferromagnetic metallic state in $\rm La_{1-x}Ca_{x}MnO_3$ for $\rm (x=0.3,0.2)$ was investigated by dc conductivity, ellipsometry, and VUV…

We present a small-but-sizeable magnetic polaron picture where transport at high temperatures is activated while at low temperatures it is band-like. We show that both double exchange and finite bandwidth effects are important to understand…

Metal-insulator transitions in clean, crystalline solids can be driven by two distinct mechanisms. In a conventional insulator, the charge carrier concentration vanishes, when an energy gap separates filled and unfilled electronic states.…

We report x-ray scattering studies of broad peaks located at a (0.5 0 0)/(0 0.5 0)-type wavevector in the paramagnetic insulating phases of La_{0.7}Ca_{0.3}MnO_{3} and Pr_{0.7}Ca_{0.3}MnO_{3}. We interpret the scattering in terms of…

Carbon nanotubes (CNTs) are quasi-1D nanostructures that display both high thermal conductivity and intriguing low-dimensional phonon transport phenomena. In comparison to the advances made in the theoretical calculation of the lattice…

We present infrared and Raman measurements of magnetite (Fe_3O_4). This material is known to undergo a metal-insulator and a structural transition (Verwey transition) at T_V=120K. At temperatures below T_V, we observe a strong gap-like…

We report on electric-field and temperature dependent transport measurements in exfoliated thin crystals of Bi$_{2}$Se$_{3}$ topological insulator. At low temperatures ($< 50$ K) and when the chemical potential lies inside the bulk gap, the…

The resistivity in the ferromagnetic state of flux-grown La_{2/3}(Pb,Ca)_{1/3}MnO_3 single crystals, measured in magnetic fields up to 7 T, reveals a strong quadratic temperature dependence at and above 50 K. At lower temperatures, this…

Neutron diffraction data presented in this paper demonstrates the relevance of lattice displacement above TC, in our understanding of the evolution of the crystal structure with temperature in the layered CMR manganite La1.2Sr1.8Mn2O7. The…

We report measurements of the resistance of silicon MOSFETs as a function of temperature in high parallel magnetic fields where the 2D system of electrons has been shown to be fully spin-polarized. A magnetic field suppresses the metallic…

Intrinsic magnetic topological insulators provide an ideal platform to achieve various exciting physical phenomena. However, this kind of materials and related research are still very rare. In this work, we reported the electronic and…

The Nd0.6Sr0.4MnO3 manganite system exhibits a phase transition from paramagnetic insulating (PMI) to ferromagnetic metallic (FMM) state around its Curie temperature TC = 270 K (bulk). The morphology-driven changes in the kinetically…

Current-induced switching from metallic to insulating state is observed in phase-separated states of (La_{1-y}Pr_y)_{0.7}Ca_{0.3}MnO_3 (y=0.7) and Nd_{0.5}Ca_{0.5}Mn_{1-z}Cr_zO_3 (z=0.03) crystals. Application of magnetic fields to this…

A giant low-frequency, in-plane dielectric constant, eps~10^6, for epitaxial thin films of Ca(1-x)La(x)MnO(3) (x<=0.03) was observed over a broad temperature range, 4K <= T 300K. This phenomenon is attributed to an internal barrier-layer…

Photogenerated carrier transport and recombination in metal halide perovskites are critical to device performance. Despite considerable efforts, sample quality issues and measurement techniques have limited the access to their intrinsic…

The temperature dependence of the complex optical properties of the layered phosphide material EuCd$_2$P$_2$ have been measured over a wide frequency range above and below $T_{\rm N} \simeq 11.5$ K for light polarized in the $a-b$ planes.…

The correlation between magnetic properties and microscopic structural aspects in the diluted magnetic semiconductor Ge$_{1-x}$Mn$_{x}$Te is investigated by x-ray diffraction and magnetization as a function of the Mn concentration $x$. The…

We measure the temperature-dependent carrier density and resistivity of the topological surface state of thin exfoliated Bi2Se3 in the absence of bulk conduction. When the gate-tuned chemical potential is near or below the Dirac point the…