Regarding this array: what compositional modifications may be made to SrTiO3 in an attempt to induce new properties or enhance existing ones?
a) Doping with foreign elements such as La, Ca, or Nb to alter its electronic properties
b) Changing the crystal structure through high-pressure techniques to potentially enhance its properties
c) Introducing defects or vacancies within the crystal lattice to influence its physical characteristics
d) Adding additional layers of different materials through processes like molecular beam epitaxy to create new interfaces and manipulate its functionality