Effect of deep-defect excitation on mechanical energy dissipation of single-crystal diamond

TL;DR

This study investigates how deep defects in single-crystal diamond influence its mechanical energy dissipation across a wide temperature range, revealing temperature-dependent dissipation peaks and the impact of impurity removal on resonator quality.

Contribution

It provides the first combined experimental and theoretical analysis of deep defect effects on diamond's mechanical dissipation up to 973 K, introducing a two-level defect model.

Findings

Energy dissipation increases with temperature and shows peaks due to phonon-defect interactions.

Removing boron impurities significantly enhances the quality factor of diamond resonators.

Deep nitrogen defects contribute to low intrinsic energy dissipation at high temperatures.

Abstract

The ultra-wide bandgap of diamond distinguishes it from other semiconductors, in that all known defects have deep energy levels that are inactive at room temperature. Here, we present the effect of deep defects on the mechanical energy dissipation of single-crystal diamond experimentally and theoretically up to 973 K. Energy dissipation is found to increase with temperature and exhibits local maxima due to the interaction between phonons and deep defects activated at specific temperatures. A two-level model with deep energies is proposed to well explain the energy dissipation at elevated temperatures. It is evident that the removal of boron impurities can substantially increase the quality factor of room-temperature diamond mechanical resonators. The deep-energy nature of nitrogen bestows single-crystal diamond with outstanding low-intrinsic energy dissipation in mechanical resonators at room temperature or above.