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<p>The present study examines the impact of stacking faults (SFs) on the structural, electronic, mechanical, and thermodynamic properties of the zincblende AlAs compound (B<sub>3</sub>). The calculations were based on density-functional theory (DFT), specifically using zincblende supercells with stacking along the [111] crystallographic direction. Both the stacking fault energy (SFE) and electronic band structure were obtained from total energy calculations. Among the stacking faults, type II exhibited the lowest SFE, followed by type I. To address the underestimation of bandgaps typically associated with density functional theory (DFT), a generalized gradient approximation and modified Becke–Johnson functional were used. The findings indicate that type I stacking faults possess an indirect bandgap lower than that of pristine crystals. The reduction in the bandgap facilitates the formation of quantum-well regions at the zincblende–wurtzite interfaces. Notably, a reduction in the SFE of type II SFs was observed, accompanied by an increase in the bandgap energy. This observation is particularly unexpected, as it has not been documented in previous studies, to the best of our knowledge. This bandgap widening is attributed to carrier confinement induced by the local structural distortion. The stress–strain method was used to determine elastic constants. Type II stacking faults (SFs) weaken semiconductors by initiating dislocations while enhancing ductility through partial dislocations. The shear modulus (<i>G</i>), Young’s modulus (<i>E</i>), and Vickers hardness (<i>H</i><sub>v</sub>) decreased with type II SFs, while the bulk modulus (<i>B</i>) increased, indicating greater incompressibility. Thermodynamic behaviors, including the Gibbs free energy (<i>G</i>), bulk modulus (<i>B</i>), and thermal expansion coefficient (<i>α</i>), were analyzed at constant pressure versus temperature. Results show that planar imperfections enhance stability, while stacking faults improve compression resistance and reduce <i>α</i> through phonon scattering and bond stiffening.</p>

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Impact of Intrinsic Stacking Faults on the Electronic, Mechanical, and Thermodynamic Properties of Zincblende AlAs: A DFT Study

  • 期刊论文

  • 发表日期：

    2026年3月30日

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  • Mohamed Hammadi,
  • Said Meskine,
  • Abdelkader Boukortt,
  • Khadidja Missoum

摘要

The present study examines the impact of stacking faults (SFs) on the structural, electronic, mechanical, and thermodynamic properties of the zincblende AlAs compound (B3). The calculations were based on density-functional theory (DFT), specifically using zincblende supercells with stacking along the [111] crystallographic direction. Both the stacking fault energy (SFE) and electronic band structure were obtained from total energy calculations. Among the stacking faults, type II exhibited the lowest SFE, followed by type I. To address the underestimation of bandgaps typically associated with density functional theory (DFT), a generalized gradient approximation and modified Becke–Johnson functional were used. The findings indicate that type I stacking faults possess an indirect bandgap lower than that of pristine crystals. The reduction in the bandgap facilitates the formation of quantum-well regions at the zincblende–wurtzite interfaces. Notably, a reduction in the SFE of type II SFs was observed, accompanied by an increase in the bandgap energy. This observation is particularly unexpected, as it has not been documented in previous studies, to the best of our knowledge. This bandgap widening is attributed to carrier confinement induced by the local structural distortion. The stress–strain method was used to determine elastic constants. Type II stacking faults (SFs) weaken semiconductors by initiating dislocations while enhancing ductility through partial dislocations. The shear modulus (G), Young’s modulus (E), and Vickers hardness (Hv) decreased with type II SFs, while the bulk modulus (B) increased, indicating greater incompressibility. Thermodynamic behaviors, including the Gibbs free energy (G), bulk modulus (B), and thermal expansion coefficient (α), were analyzed at constant pressure versus temperature. Results show that planar imperfections enhance stability, while stacking faults improve compression resistance and reduce α through phonon scattering and bond stiffening.