Chris Van de Walle1
University of California, Santa Barbara1
Chris Van de Walle1
University of California, Santa Barbara1
Quantum technologies have become a top research priority. Point defects in semiconductors provide a platform that combines the environmental isolation necessary to maintain coherence with the ability to perform electrical and optical manipulation [1]. The NV center in diamond has been widely studied as an individually-addressable quantum system; our goal is to identify centers in other materials that exhibit similarly favorable properties. Building on the first-principles methodology for point-defect calculations [2], we have developed the capability to predict transition energies, lineshapes of optical transitions [3,4], and rates of radiative [5] and nonradiative [6] transitions, relevant for intersystem crossings. I will illustrate these developments with examples for AlN [7] and hexagonal boron nitride (h-BN) [8,9]. Single-photon emission has been observed in h-BN at ~2 eV and at 4.1 eV, but microscopic identification of the underlying point defects has proved elusive. We attribute the single-photon emission at ~2 eV to boron dangling bonds [8], and the 4.1 eV emission to a C-C dimer [9].<br/><br/>Work performed in collaboration with A. Alkauskas, L. C. Bassett, C. E. Dreyer, A. Janotti, J. Lyons, M. Maciaszek, M. Mackoit, L. Razinkovas, M. Turiansky, J. Varley, J. Weber, and Q. Yan, and supported by DOE and NSF.<br/><br/>[1] C. E. Dreyer <i>et al.</i>, Annu. Rev. Mater. Res. <b>48</b>, 1 (2018).<br/>[2] C. Freysoldt <i>et al.</i>, Rev. Mod. Phys. <b>86</b>, 253 (2014).<br/>[3] A. Alkauskas <i>et al.</i>, New J. Phys. <b>16</b>, 073026 (2014).<br/>[4] L. Razinkovas <i>et al.</i>, Phys. Rev. B <b>104</b>, 045303 (2021).<br/>[5] C. E. Dreyer<i> et al.</i>, Phys. Rev. B <b>102</b>, 085305 (2020).<br/>[6] M. E. Turiansky<i> et al.</i>, Comput. Phys. Commun. <b>267</b>, 108056 (2021).<br/>[7] J. B. Varley <i>et al.</i>, Phys. Rev. B <b>93</b>, 161201 (2016).<br/>[8] M. E. Turiansky <i>et al.</i>, Phys. Rev. Lett. <b>123</b>, 127401 (2019).<br/>[9] M. Mackoit-Sinkeviciene <i>et al.</i>, Appl. Phys. Lett. <b>115</b>, 212101 (2019).