Mechanical and electronic properties of strained Ge nanowires using ab initio real-space pseudopotentials

Theoretical calculations with real-space pseudopotentials constructed within density-functional theory are employed to calculate mechanical and electronic properties for [100], [110], and [111] germanium nanowires up to 2.7 nm in diameter. Uniaxial strain is applied to wires within the range of -5 t...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2012-09, Vol.86 (11), Article 115331
Main Authors: Lee, Alex J., Kim, Minjung, Lena, Charles, Chelikowsky, James R.
Format: Article
Language:English
Subjects:
Band structure of solids
Condensed matter
Energy gaps (solid state)
Mathematical analysis
Nanowires
Pseudopotentials
Strain
Wire
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Summary:Theoretical calculations with real-space pseudopotentials constructed within density-functional theory are employed to calculate mechanical and electronic properties for [100], [110], and [111] germanium nanowires up to 2.7 nm in diameter. Uniaxial strain is applied to wires within the range of -5 to 5%. The strain energy is used to calculate the Young's modulus for each wire, whose values are found to increase with diameter up to approximately the theoretical bulk values. Electronic band structures are calculated for each wire with respect to strain, and from these structures band gaps are obtained. The size and the nature (direct or indirect) of the band gaps are found to be influenced by the growth direction, wire size, and strain amount. Carrier effective masses are calculated from the band structures and may be discontinuous under certain amounts of strain owing to band crossing, which can correspond to sudden drops in carrier mobilities.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.86.115331