| | α | Angle between the [0001] direction and the dislocation |
| | | line in polar spherical coordinate |
| | β | Angle of the polar spherical coordinate |
| | ai, a | Hexagonal lattice vectors and their length |
| | b, b | Burgers vector and its length |
| | bs, be | Screw and edge components of the Burgers vector |
| | c, c | Hexagonal lattice vector along [0001] and its length |
| | γ | Angle between the dislocation line and the normal to |
| | | the free surface |
| | C | Stiffness tensor |
| | cij | Elastic constants |
| | Δ | Fractional change in volume |
| | δ | Dislocation slip plane |
| | dF | Differential change in Helmholtz free energy |
| | εij | Strain components |
| | εd | Strain tensor associated to the dislocation |
| |  | Dislocation energy |
| | d | Elastic part of the dislocation energy |
| | core | Dislocation core energy |
| | f | Direction of the upper point of the threading dislocation |
| | | |
| | ζx, ζy | Shear angles |
| | ηij | Shear strain components |
| | θ | Angle between the Burgers vector and the dislocation line |
| | h = hf | Layer thickness |
| | H | Bulk modulus |
| | hc | Critical thickness |
| | ι | Angle of the polar spherical coordinate |
| | K | Rotation matrix |
| | K | Pre-logarithmic coefficient of the dislocation energy |
| | KG,ijk | Reaction rate of two glissile threading dislocations of i and |
| | | j types |
| | KGS,ijk | Reaction rate of one glissile threading dislocation |
| | | of i type and one glissile threading dislocation of j types |
| | KS,ijk | Reaction rate of two sessile threading dislocations of i and |
| | | j types |
| | λ | Lamé constant |
| | l | Dislocation line direction |
| | μ | Shear modulus or Lamé constant |
| | m | Direction of the misfit dislocation |
| | ν | Poisson’s ratio |
| |
| | nf | Normal of the free surface |
| | ng | Normal of the slip plane |
| | Ω,Ωij | Transformation tensor and components |
| | p | Effective pressure acting on a volume element |
| | ρ = ρTD | Total threading dislocation density |
| | ρG | Glissile threading dislocation density |
| | ρi | Density of the i-type threading dislocations |
| | ρMD | Misfit dislocation density |
| | ρS | Sessile threading dislocation density |
| | R | Outer cut-off radius |
| | rc | Radius of the dislocation core or inner cut-off radius |
| | ς | Angle of the polar spherical coordinate |
| | σij | Stress components |
| | σY | Standard deviation of Young’s modulus |
| | σd | Stress tensor associated with the dislocation |
| | σm | Tensor associated with the misfit stress |
| | S | Compliance tensor |
| | sij | Elastic compliances |
| | u | Interatomic distance in the wurtzite structure |
| | u, uij | Displacement vector and components |
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| | ϕ | Angle between the slip plane and the normal to the |
| | | film-substrate interface |
| | vG | Velocity of the upper point of one glissile TD along |
| | | the free surface |
| | vS | Velocity of the upper point of one sessile TD along |
| | | the free surface |
| |  | Work done by the misfit stress |
| | w | Strain energy per unit of volume |
| | x | Composition of an alloy |
| | χ | Angle associated with pure tilt boundary |
| | Y | Elastic or Young’s modulus |
| | ⟨Y ⟩ | Average elastic modulus |
| | ζ | Angle associated with pure tilt boundary |
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