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HL: Fachverband Halbleiterphysik

HL 39: Materials and devices for quantum technology II

HL 39.8: Vortrag

Mittwoch, 18. März 2020, 12:00–12:15, POT 112

Local vibrational modes of Si vacancy spin qubits in SiC — •z. shang¹, y. berencén¹, a. hashemi², a. krasheninnikov^1,2, g. astakhov¹, h-p. komsa², and p. erhart³ — ¹Institute of Ion Beam Physics and Materials, HZDR, Dresden, Germany — ²Department of Applied Physics, Aalto University, Aalto, Finland — ³Department of Physics, Chalmers University of Technology, Gothenburg, Sweden

Since the first demonstration of promising quantum properties of intrinsic point defects in SiC, they have been used to implement room-temperature quantum emitter as well as to realize quantum sensing. Radiative recombination of these point defects is accompanied by phonon emission due to the interaction with crystal vibrations. This process results in the so-called phonon side band (PSB). A high ratio of the emitted light from the zero-phonon line (ZPL) to the all emitted light, the Debye-Waller factor, is required for the implementation of quantum repeaters. Although the understanding of the PSB is important for quantum applications, it has not been yet investigated systematically in SiC.In this work, we uncover the local vibrational modes of the Si vacancy spin qubits in pristine 4H-SiC. The ZPL and six equally separated phonon replicas are observed in the optically-detected magnetic resonance spectra. We present first-principles calculations of the photoluminescence line-shape, which are in excellent agreement with the experiments. We experimentally obtain the resonance phonon energy and the Debye-Waller factor associated with the Si vacancy qubits. Our approach can be applied to a large variety of optically-active spin defects in wide-bandgap materials.