Abstract
Several metallic -based systems, including reduced , Nb-doped , and two-dimensional electron gas at the interface, have been epitaxially fabricated on various substrates inducing different strain, from −2.98% (compressive) to +0.99% (tensile). For all the -based systems, strain reduces conductivity. Tensile strain, however, is much more effective at reducing conductivity compared to compressive strain. Further, carrier mobility is found to be more sensitive to strain than carrier density. Calculations based on density functional theory show that strain can break the cubic symmetry of octahedron, lift the degeneracy of orbitals, and reduce the number of available states at the bottom of the conduction band to cause low carrier mobility. Our results show the critical features of strain effect on the conducting -based systems, and shed some light on strain engineering of these functional materials.
- Received 13 April 2014
- Revised 18 August 2014
DOI:https://doi.org/10.1103/PhysRevB.90.125156
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