Two-path phonon interference resonance induces a stop band in a silicon crystal matrix with a multilayer array of embedded nanoparticles

Abstract

In this work, we report a new stop-band formation mechanism by performing the atomistic Green's function calculation and the wave-packet molecular dynamics simulation for a system with germanium-nanoparticle array embedded in a crystalline silicon matrix. When only a single nanoparticle is embedded, the local resonance, induced through destructive interference between two different phonon wave paths, gives rise to several sharp and significant transmittance dips. On the other hand, when the number of embedded nanoparticles further increases to ten, a stop band with complete phonon reflection is formed due to the two-path resonance Bragg-like phonon interference. The wave packet simulations further uncover that the stop band originates from the collective phonon resonances at the embedded nanoparticles. Compared with the traditional stopband formation mechanism that is the single-path Bragg reflection, the resonance mechanism has a significant advantage in not requiring the strict periodicity in the embedded nanoparticles array.We also demonstrate that the stop band can significantly suppress thermal conductance in the lowfrequency regime. Our work provides a robust, scalable, and easily modulable stop-band formation mechanism, which opens a new degree of freedom for phononics-related heat control.

Nano-phononic metamaterials enable an anomalous enhancement in the interfacial thermal conductance of the GaN/AlN heterojunction

“…This effect is caused mainly by the single-path Bragg-like phonon interference. 45 When the periodic length of the SL decreases, the phonon transmission of low-frequency phonons recovers to a level comparable to that of the HJ, which leads to an increased ITC.…”

Emerging theory and phenomena in thermal conduction: A selective review

“…In addition to the superlattice structure, Hu et al [94] proposed an approach based on two-path phonon interference to achieve a stop band and the total reflection of the phonons in a multilayer array with a crystalline silicon matrix and embedded germanium nanoparticles. As shown in Figure 3(b), the phonon transmission decreases dramatically as the number of nanoparticle layers increases.…”

Phonon transport in the nano-system of Si and SiGe films with Ge nanodots and approach to ultralow thermal conductivity

“…To this aim, a lot of researchers have suggested unique nanostructures tailoring phonon transport in light of experiments and theories. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] A coherent phonon effect was observed at room temperature in the superlattices (SLs) with several nm periodicity. 10,18 In the twodimensional Si phononic crystals with a nanohole periodicity of ∼500 nm, the ballistic phonon particle-like transport was detected.…”

“…[20][21][22][23][24][25][26][27][28][29][30][31][32] In such materials, recent theoretical studies reported the interesting phonon wave properties indicating that a nanodot (ND) can work as a resonator in analogy with photonic crystals. 16,19 However, the actual nanostructures include unwanted and undefined structural features, such as interface defects, impurities, strain, etc., making it difficult to classify the contribution of each scattering process to phonon transport and especially to observe an interesting phonon wave effect.…”