Towards Identifying the PL6 Center in SiC: From First-Principles Screening to Hyperfine Validation of Competing Defect Candidates

Abstract

The PL6 color center in 4H-SiC, known for its excellent ambient-temperature spin and optical properties, has an unresolved microscopic origin. In this first-principles study, we systematically investigate potential structures to clarify its nature. We first rigorously examine the DV-antisite hypothesis (a divacancy paired with a carbon antisite, ${\mathrm{C}}_{\mathrm{Si}}$), analyzing the energetic, electronic, and spin properties of various $V_{\mathrm{Si}}{V}_{\mathrm{C}}+{\mathrm{C}}_{\mathrm{Si}}$ configurations. Two ${\mathrm{C}}_{3v}$-symmetric $\mathrm{kk}+{\mathrm{C}}_{\mathrm{Si}}$ complexes emerge as strong candidates within this framework. Subsequently, a critical comparison of hyperfine interaction signatures is performed between these candidates, the alternative OV model [specifically OV(hh) and OV(kk), an oxygen replacing C together with a Si vacancy], and experimental data. This analysis demonstrates that the OV(hh) structure more accurately reproduces PL6's hyperfine features. Furthermore, re-evaluation of the proposed OV(hk) model for the related PL5 center reveals zero-field splitting parameter $E$ inconsistencies with experimental results, suggesting that PL5 and PL6 may have distinct origins. These findings provide crucial theoretical insights and motivate targeted experimental validation for these quantum defects.

References in corpus (7)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Coherent control of single spins in silicon carbide at room temperature
• Isolated electron spins in silicon carbide with millisecond-coherence times
• Optical charge state control of spin defects in 4H-SiC
• Optical polarization of nuclear spins in silicon carbide
• Identification of Si-vacancy related room temperature qubits in 4H silicon carbide

Cited by in corpus (1)

• Photoelectrical detection and characterization of divacancy and PL5-PL7 spins in silicon carbide