Surface Acoustic Waves

Rayleigh waves, surface disorder, and phonon localization in nanostructures

“…µ is also known as the shear modulus and µ > 0. Thermodynamic stability requires λ > − 2 3 µ [6], but λ > 0 for most materials [17].…”

“…There are many types of surface waves in atomic and inhomogeneous elastic materials [8,9,17]. Graphene nanoribbons are no exception and support a number of in-plane and out-of-plane edge modes, with properties that depend on the terminating atoms [63].…”

“…1) are the only type of surface wave [17]. Here, we briefly review some important facts about Rayleigh waves [5,6].…”

“…It has long been known that bulk waves (longitudinal and transverse) can be converted to Rayleigh waves at rough [10,11] or otherwise disordered [12][13][14] surfaces, but not at smooth ones [6,15]. So, early work on Rayleigh wave scattering focused on their decay into bulk waves in the presence of disorder [10,12,13,16,17], but did not address phonon transport. Nakayama [14] identified Rayleigh-to-bulk mode conversion as a cause of diffuse phonon-surface scattering, which is important to many phonon transport models [18][19][20].…”

Iterative solution of the generalized Love's problem in anisotropic media

“…The first surface is stress-free and the second is the interface between the layer and a homogeneous anisotropic elastic half-space H. The mass density and the elastic moduli in L are assumed to depend on the distance from S 0 and may be discontinuous across S 1 . In order to allow for SH waves we suppose that the layer L and the half space H admit either a common plane of material symmetry S ⊥ which is normal to S 0 and S 1 or a second axis of symmetry which is parallel to S 0 and S 1 (see for example [4]). …”