Christopher Kohler 2003 J. Phys.: Condens. Matter 15 133 doi:10.1088/0953-8984/15/2/313
Christopher Kohler
Show affiliationsStrain distributions around a Ge quantum dot (QD) buried in a Si spacer layer are investigated theoretically by means of classical molecular dynamics simulations using the Tersoff potential. Applying periodic boundary conditions laterally, two-dimensional superlattices of QDs are obtained. Strain distributions in systems of different sizes and lattice misorientations are computed in order to explain possible vertical correlations in self-organized three-dimensional QD superstructures. Generally, the strain of relaxed systems displays an oscillatory behaviour as a function of the distance from the QD. For QD systems with growth direction [001], a simple fitting function is used to describe the strain along a vertical path above the QD by an oscillation and a decay according to a power law. For QDs with the shape of a truncated pyramid, the planar strain decays by a power of approximately −3. The period of the oscillation is nearly proportional to the QD superlattice constant and decreases with increasing coordination number of the QD superlattice. In misoriented systems with a small tilt angle about the [110] axis, the region of tensile planar strain above the QD is bent in the direction opposite to the misorientation causing a vertical correlation with lateral shift. For a tilt angle ≈55°, no strain oscillation is found which implies a perfect vertical correlation.
Issue 2 (22 January 2003)
Received 7 August 2002
Published 20 December 2002
Christopher Kohler 2003 J. Phys.: Condens. Matter 15 133
Igor D Kaganovich et al 2006 New J. Phys. 8 278
Chopin Soo 2002 Class. Quantum Grav. 19 1051
S Emura et al 2009 J. Phys.: Conf. Ser. 190 012102
R Atkinson and G A Jones 1976 J. Phys. D: Appl. Phys. 9 L131
Li Zhi and Han Chong-Zhao 2002 Chinese Phys. 11 666
Y Yamada et al 2006 Metrologia 43 L23
G Beutier et al 2009 New J. Phys. 11 113026
Helena Maier-Metz 1998 Eur. J. Phys. 19 137
O Giraud 2004 J. Phys. A: Math. Gen. 37 2751