The quadratic low-temperature dependence of resistance in ordinary metals is determined by the momentum relaxation due to electron-electron scattering presence Umklapp processes and on impurities. In without inversion center spin-orbit interaction electrons with crystal lattice lifts spin degeneracy electron states splits each band two bands. temperature collisions rate found using matrix kinet...

Bismuth oxyselenide (Bi$_2$O$_2$Se) attracts great interest as a potential n-type complement to p-type thermoelectric oxides in practical applications. Previous investigations were generally focused on polycrystals. Here, we performed study the properties of Bi$_2$O$_2$Se single crystals. Our samples exhibit electron mobility high 250 cm$^2.$V$^{-1}$.s$^{-1}$ and thermal conductivity low $2$ W....

D. L. Nika,1,2 E. P. Pokatilov,1,2 A. S. Askerov,2 and A. A. Balandin1,3,* 1Nano-Device Laboratory, Department of Electrical Engineering, University of California–Riverside, Riverside, California 92521, USA 2Department of Theoretical Physics, Moldova State University, Chisinau, MD-2009, Republic of Moldova 3Materials Science and Engineering Program, Bourns College of Engineering, University of ...

We have measured the thermal resistance of a 152-nm-diameter carbon nanofiber before and after a platinum layer was deposited on the contacts between the nanofiber and the measurement device. The contact resistance was reduced by the platinum coating for about 9–13% of the total thermal resistance of the nanofiber sample before the platinum coating. At a temperature of 300 K, the axial thermal ...

Thermal conductivity in non-metallic crystalline materials results from cumulative contributions of phonons that have a broad range of mean free paths. Here we use high frequency surface temperature modulation that generates non-diffusive phonon transport to probe the phonon mean free path spectra of GaAs, GaN, AlN, and 4H-SiC at temperatures near 80 K, 150 K, 300 K, and 400 K. We find that pho...

Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on Si(111))3)-Ag, Si(111))3)-Au, and Si(111)A21 3A21-(Ag1Au). For Si(111))3)-Ag the Fermi surface consists of small electron pockets popul...

We report a resistive investigation of superconductivity in the system La2 xSrxCuO4 y on samples which have been analysed by thermogravimetric techniques for oxygen deficiency determination. A maximum superconductive transition temperature is observed in La2 xSrxCuO4 y near the tetragonal-orthorhombic phase transition, together with a resurgence of high temperature superconductivity in non-subs...

We present the electron-position momentum distribution measured in single crystals of 7-tin (Sno.~Ino. 2) by 2D angular correlation of positron annihilation radiation. The Fermi sphere and its Umklapp components up to the 3rd order are easily distinguishable. The deviation of the Fermi surface from a sphere is studied in detail, and compares nicely with theory based on Linear Muffin Tin Orbital...

We have investigated experimentally the thermal conductivity of suspended twisted bilayer graphene. The measurements were performed using an optothermal Raman technique. It was found that the thermal conductivity of twisted bilayer graphene is lower than that of monolayer graphene and the reference, Bernal stacked bilayer graphene in the entire temperature range examined (∼300-700 K). This find...