Modification of electronic, optical, and magnetic properties of titanate nanotubes by metal intercalation

Abstract

The electronic, optical, and magnetic properties of ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$ are investigated by first-principles density function theory calculations, and also the modifications of these properties by metal intercalation in ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$. It is shown that the band gap of ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$ may be significantly reduced by Fe or Ni intercalation, and that the intercalated Fe or Ni may form a one-dimensional (1D) channel via overlapping $3d$ orbitals along the [010] direction in the interlayer region. These overlapping $3d$ orbitals result in an extended band within the band gap region of ${\mathrm{H}}_{2}{\mathrm{Ti}}_{3}{\mathrm{O}}_{7}$ and below its Fermi level, and this band in turn results in a low effective mass for hole transport along the 1D channel and a large magnetic moment for the Fe or Ni intercalated material.