نتایج جستجو برای: metallic superlattice
تعداد نتایج: 41728 فیلتر نتایج به سال:
We have found experimentally that the shot noise of the tunneling current I through an undoped semiconductor superlattice is reduced with respect to the Poissonian noise value 2eI, and that the noise approaches 1/3 of that value in superlattices whose quantum wells are strongly coupled. On the other hand, when the coupling is weak or when a strong electric field is applied to the superlattice, ...
We report on a broadband GaAs/AlAs superlattice detector for THz radiation; a THz field reduces the current through a superlattice, which is carried by miniband electrons, due to modulation of the Bloch oscillations of the miniband electrons. We studied the detector response, by use of a free electron laser, in a large frequency range ~5–12 THz!. The responsivity showed strong minima at frequen...
The authors report the growth of ZnSe/ZnSeTe superlattice nanotips on oxidized Si(100) substrate. It was found the nanotips exhibit mixture of cubic zinc-blende and hexagonal wurtzite structures. It was also found that photoluminescence intensities observed from the ZnSe/ZnSeTe superlattice nanotips were much larger than that observed from the homogeneous ZnSeTe nanotips. Furthermore, it was fo...
We report the growth of self-assembled ErAs islands embedded in GaAs by molecular beam epitaxy. The nucleation of ErAs on GaAs occurs in an island growth mode leading to spontaneous formation of nanometer-sized islands. Several layers of ErAs islands separated by GaAs can be stacked on top of each other to form a superlattice. X-ray diffraction shows superlattice fringes from such samples. Pump...
The structure and magnetic properties of an InGaAs/Fe(3)Si superlattice in a cylindrical geometry are investigated by electron microscopy techniques, x-ray diffraction and magnetometry. To form a radial superlattice, a pseudomorphic InGaAs/Fe(3)Si bilayer has been released from its substrate self-forming into rolled-up microtubes. Oxide-free interfaces as well as areas of crystalline bonding ar...
Femtosecond pulses are used to excite A1g optical phonons in Bi2Te3, Sb2Te3, and Bi2Te3 /Sb2Te3 superlattice. Time-resolved reflectivity measurements show both the low-frequency and high-frequency components of A1g phonon modes. By comparing the phonon lifetime, it is found that the scattering rate inverse of lifetime in superlattice is significantly higher than those in Bi2Te3 and Sb2Te3. This...
Tetragonal ferroelectric/ferroelectric BaTiO(3)/PbTiO(3) superlattice under uniaxial tensile stress along the c axis is investigated from first principles. We show that the calculated ideal tensile strength is 6.85 GPa and that the superlattice under the loading of uniaxial tensile stress becomes soft along the nonpolar axes. We also find that the appropriately applied uniaxial tensile stress c...
The geometrical, chemical and ferroelectric properties of a new nanoscale short-period three-component SrTiO3/BaTiO3/PbTiO3 perovskite superlattice are investigated using a first principles density functional approach. The study focuses on varying the thickness of each component in the superlattice and determining the resulting lattice distortion and total polarization. Thicknesses of up to thr...
In a superlattice containing a finite number of periods, the allowed values of the Bloch wave number form a discrete set, and the dynamics of an electron through k-space under the influence of an external force is necessarily that of a superposition wave packet composed of multiple Bloch waves. The present paper investigates this dynamics for a particularly simple class of “kcompact” wave packe...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید