Phonon interference and thermal conductance reduction in atomic-scale metamaterials

Abstract

We introduce and model a three-dimensional (3D) atomic-scale phononic metamaterial producing two-path phonon interference antiresonances to control the heat flux spectrum. We show that a crystal plane partially embedded with defect-atom arrays can completely reflect phonons at the frequency prescribed by masses and interaction forces. We emphasize the predominant role of the second phonon path and destructive interference in the origin of the total phonon reflection and thermal conductance reduction in comparison with the Fano-resonance concept. The random defect distribution in the plane and the anharmonicity of atom bonds do not deteriorate the antiresonance. The width of antiresonance dip can provide a measure of the coherence length of the phonon wave packet. All our conclusions are confirmed both by analytical studies of the equivalent quasi-1D lattice models and by numerical molecular dynamics (MD) simulations of realistic 3D lattices.Two-photon interference can result in a total cancellation of the photon output because of the coalescence of the two single photons, which was first observed by Hong et al. [1]. This interference effect occurs because two possible photon paths interfere destructively, which produces the famous "Hong-Ou-Mandel (HOM) dip" in the detection probability of the output photons. The HOM dip has since then been demonstrated in both the optical [2,3] and microwave[4] regime. In particular, two-photon destructive interference was recently demonstrated in a 3D optical metamaterial [5]. Similar destructive interference effect which results in a total reflection can be also realized in a phonon system. For the sound waves, the two-path phonon interference antiresonance was first described in Ref. [6], where the anomalous zero-transmission and total absorption of long-wavelength acoustic waves in a crystal with 2D (planar) defect were related with the destructive interf erence between the two possible phonon paths: through the nearest-neighbor bonds and through the non-nearest-neighbor bonds which couple directly crystal layers adjacent to the defect atomic plane.Constant endeavour has been devoted to the precisely control of heat conduction. Recent efforts concentrated on reducing the thermal conductivity κ via nanostructured materials with superlattices [7,8] and embedded nanoparticles [9][10][11]. Most works attributed the reduction of κ to the decreased phonon life time and thus the mean free path (MFP), which belong to the particle description of heat conduction. However, the role of destructive phonon interference in the reduction of κ is much less understood in the wave picture of thermal transport.In this Letter we introduce and model a realistic 3D atomic-scale phononic metamaterial that allows for manipulating the flow of thermal energy. Two-path phonon interference is generated by exploiting the phonon reflection on internal interfaces embedded with defect-atom arrays. The 2D planar defects force phonons to propagate through two paths: through unperturbed (matrix) and perturbed ...

Tuning the thermal conductance of molecular junctions with interference effects

“…However, if one assumes that atomically thin, single crystal planes can be manipulated at will, also higher-energy or short-wavelength phonons can in principle be affected, since structural length scales are of interatomic distance. Thus, Han et al 5 theoretically proposed the suppression of heat transport using defect atom arrays embedded in a single crystal plane. To inhibit the heat flow, the authors exploited the destructive interference between two phonon paths.…”

Phononic thermal resistance due to a finite periodic array of nano-scatterers

“…Other strategies have been highlighted, such as the addition of a new material to the solid/solid coupling or modulating the roughness [10]. Lattice dynamics [11,12], Green"s functions [13] and molecular dynamics are often employed for the calculations [14][15][16]. We observe that the two commonly applied models, the acoustic mismatch model (AMM) and diffuse mismatch model (DMM), do not necessarily lead to values that are comparable to the available experimental data [1,15,17,18].…”

“…The theory has been applied to predict the thermal resistance of different types of junction [15,16,39,40]. Here, we consider the hole array as a barrier between two parts of same material.…”

Acoustic total transmission and additional modes in the metamaterials embedded with defects

“…Metamaterials, [1][2][3][4][5] as artificial materials possessing unusual parameters, have drawn extensive attention. Zhu et al 6 studied the concept of light amplification in a system of zero-index metamaterials (ZIMs) with gain inserts.…”