Dopant Induced Stress and Strain Enhanced Doping

We report an intriguing dopant induced electronic stress effect. A foreign dopant atom induces a lattice stress. Conventional dopant induced stress is due to the different atomic sizes between the dopant and host element. Here, we discovered an intriguing dopant induced electronic stress effect. First principles calculation reveals that even a dopant with the same atomic size as the host atom induces a lattice stress of electronic origin, because it has either one more or one less electron than the host. We also found that the electronic stress exhibits a nonlinear dependence on strain, different from the conventional atomic stress effect. In general, the competition between the atomic stress and electronic stress determines the overall stress induced by a dopant, which in turn determines how external strain will change the doping energy.