Measuring bulk and surface acoustic modes in diamond by angle-resolved Brillouin spectroscopy

Abstract

The acoustic modes of diamond not only are of profound significance for studying its thermal conductivity, mechanical properties and optical properties, but also play a determined role in the performance of high-frequency and high-power acoustic wave devices. Here we report the bulk acoustic waves (BAWs) and surface acoustic waves (SAWs) of single crystal diamond by using the angle-resolved Brillouin light scattering (BLS) spectroscopy. We identify two high-velocity surface skimming bulk waves, with sound velocities of and cm/s, respectively. Furthermore, we conduct the relationship among the refractive index, incident angle and the velocities of BAWs propagating along an arbitrary direction. Our results may provide a valuable reference for fundamental researches and devices engineering in the community of diamond-based acoustic study.

Effects of Boron Doping on the Bulk and Surface Acoustic Phonons in Single-Crystal Diamond

“…The calculated in-plane phonon wavevector is q || = 0.0228 nm –1 . Two pronounced peaks are attributed to the shear-horizontal surface wave (SHW) and high-frequency pseudo-longitudinal wave (HFPLW). , The important observation is that the frequencies of these peaks decrease with an increasing boron doping concentration in diamond. The latter provides solid evidence for the phonon softening in the acoustic polarization branches.…”

“…Brillouin–Mandelstam light scattering (BMS), also referred to as Brillouin light spectroscopy (BLS), is a nondestructive optical technique that has been used extensively to study acoustic phonons in different types of materials . This technique has been employed to examine the mechanical properties of different types of diamond, e.g., polycrystalline, smooth fine-grained, and single-crystal diamond grown by chemical vapor deposition (CVD) method. − The prior studies reported the characteristics of bulk longitudinal acoustic (LA) and transverse acoustic (TA) phonons as well as the traveling surface acoustic waves (SAWs) along the high-symmetry crystallographic directions. , The elasticity coefficients of diamond were extracted from BMS data. − A recent detailed study has used the angle-resolved BMS to find the properties of SAWs along different crystallographic directions in diamond . No BMS data on the effect of boron on bulk and surface acoustic phonons in boron-doped diamond have been reported to date.…”

Brillouin Light Scattering of Halide Double Perovskite

“…Calculations of Direction-Dependent Sound Velocities: Utilizing the resultant method, we obtained the velocities of the acoustic phonons traveling along <100> and <111> directions, as mentioned in Section 3.3. It is worth noting that Xie et al [42] stated that if υ ΓU was significantly different from υ ΓX , the existence of the ΓU path (Figure 5b) would lead the υ ΓX in Equation (2) to change with θ i (υ ΓX ¼ υ 0 þ βsinθ i ), where υ 0 is the value of υ ΓX when θ i ¼ 0 and β is a θ i -dependent parameter due to the contribution of υ ΓU . However, the fitting errors for the variables were relatively larger when including the contribution of the υ ΓU , compared with the fitting results without considering the contribution of the υ ΓU , which thus have been displayed in Figure 5c,d, respectively.…”

“…Considering the sound velocity of a BAW propagating along an arbitrary direction, Xie et al proposed a resultant method to calculate the sound velocity by establishing the connection between the sound velocities of the acoustic phonons propagating along the high-symmetry axes in the first BZ and the phonon wave vector involved in the scattering, [42] which can also be applied to our work. For a given Bravais lattice, the first BZ and the corresponding irreducible wedge (IW) can be figured out.…”

“…While rotating, the propagation direction of the acoustic phonon (ΓB in Figure 5b) would tilt away from the [111] direction by an amount dictated by Snell's law, that is, the phonon wave vector would vary from the ΓL to ΓX direction in the ΓLUX plane of the IW, as indicated in Figure 5b. Utilizing the resultant method mentioned by Xie et al, [42] the velocity (υ ΓB ) of a BAW traveling along an arbitrary direction between the ΓL and ΓX direction can be written as the combination of the velocities corresponding to the ΓL (υ ΓL ) and ΓX (υ ΓX ) directions.…”