Phonons transmission through atomic interface connecting two semi-infinite 2D lattices with different meshes

A calculation of the phonon contribution to the coherent transport between two-dimensional (2D) lattices is presented in this paper. The model structure is obtained by the juxtaposition of semi-infinites square ([Formula: see text] and triangular ([Formula: see text] leads, which thus define the nanojunction [Formula: see text]/[Formula: see text] and its inverse [Formula: see text]/[Formula: see text]. We determine, numerically and by simulation, the 2D interface observables for different values of masses and elastic coupling in the nanojunction zone. The local dynamics and atomic nanojunction response to the microscopic changes, in the interfacial domain, are subjects to our investigation. The theoretical formalism based on the matching technique is applied to describe the lattice dynamics and the evanescent phonon modes, in the two studied 2D interfaces. We mainly analyze the vibration spectra, the coherent phonon transmission/reflection and the phononic transmittance through the interface, as elements of a Landauer–Büttiker type scattering matrix. The obtained results show that the nanojunction domain is an effective phonon splitter and suggest that its characteristics may be controlled by varying its nanometric parameters. The observed fluctuations are due to the coherent coupling between continuum modes and the phonons’ discrete states induced by the connected atomic sites.

Flux periodic oscillations and phase-coherent transport in GeTe nanowire-based devices

Despite the fact that GeTe is known to be a very interesting material for applications in thermoelectrics and for phase-change memories, the knowledge on its low-temperature transport properties is only limited. We report on phase-coherent phenomena in the magnetotransport of GeTe nanowires. From universal conductance fluctuations measured on GeTe nanowires with Au contacts, a phase-coherence length of about 280 nm at 0.5 K is determined. The distinct phase-coherence is confirmed by the observation of Aharonov–Bohm type oscillations for parallel magnetic fields. We interpret the occurrence of these magnetic flux-periodic oscillations by the formation of a tubular hole accumulation layer. For Nb/GeTe-nanowire/Nb Josephson junctions we obtained a critical current of 0.2 μA at 0.4 K. By applying a perpendicular magnetic field the critical current decreases monotonously with increasing field, whereas in a parallel field the critical current oscillates with a period of the magnetic flux quantum confirming the presence of a tubular hole channel.

The effect of interface angle on the thermal conductivity of Si/Ge superlattices

The special interface angle arrangement induces coherent transport of phonons and significantly improves the thermal conductivity.