One-dimensional growth of MgO film on SrTiO₃(100)

We studied the growth mode and electronic structure of MgO thin films on a Nb-doped SrTiO₃(100) single crystal by scanning tunnelling microscopy and scanning tunnelling spectroscopy. The MgO films grew in a one-dimensional (1D) chain growth mode on the SrTiO₃. It is thought that the driving forces for this growth mode are compressive stress on the MgO films and the reconstructed SrTiO₃ surface. When we imaged the MgO films at various tunnelling biases, the chains disappeared in the STM topography at a bias lower than 2.0 V and the underlying SrTiO₃(100) surface beneath the MgO films could be imaged with an atomic resolution.