Nonlocal Terahertz Wave Characteristics of Embedded Single-Walled Boron Nitride Nanotubes

چکیده مقاله

Unlike widely used carbon nanotubes, boron nitride nanotubes (BNNTs) have shown to possess stable semiconducting behavior and strong piezoelectricity. Such properties along with their outstanding mechanical properties and thermal conductivity, make BNNTs promising candidate for a verity of applications especially nanoelectronic and nanophotonic devices. Motivated by these abilities, we aim to study the terahertz wave propagation behavior of single-walled boron nitride nanotubes (SWBNNTs) when subjected to combined electro-thermo-mechanical loadings. The SWBNNT is modelled as an Euler-Bernoulli beam and is located in an elastic medium which is simulated as a Pasternak foundation. Elastic theory of the SWBNNT is reformulated using the nonlocal differential constitutive relations of Eringen. Using the principle of virtual work the governing differential equations are derived. The phase velocity of the SWBNNT is obtained based on a analytical method. This study includes the influences of nonlocal effect, wave number, aspect ratio, and elastic medium constant on the phase velocity of SWBNNT. Results indicate that the present theoretical study highlights the significance of the effects of small-scale parameter on wave propagation in SWBNNT. It is found that the difference of wave propagation characteristics between the nonlocal theory and the classical beam models is significant at higher wave numbers. This difference, however, may be ignored at lower wave numbers. The underlying reason for this is that the effect of small length scale parameter becomes remarkably important at higher wave numbers.