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

The electronic, optical, and magnetic properties of H₂Ti₃O₇ are investigated by first-principles density function theory calculations, and also the modifications of these properties by metal intercalation in H₂Ti₃O₇. It is shown that the band gap of H₂Ti₃O₇ 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 H₂Ti₃O₇ 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.