Competing conduction mechanisms of two-dimensional electrons and bulk-like electrons in the n-type surface of the naturally oxidized p-type HgCdTe thin film

The surface transport properties of naturally oxidized p-type Hg _0.776Cd _0.224Te thin film were investigated in the magnetic-field region 0-14 T and in the temperature region 8-300 K. The Hall electron concentration increases with temperature, while the surface concentration of the two-dimensional electrons in the naturally oxidized surface, calculated by Shubnikov-de Haas oscillations, decreases as temperature increases at temperatures below 20 K. The contradiction and the extraordinary quantum Hall filling factors are accounted for by assuming extra bulk-like electrons in the surface region, which dominate the surface transport properties at temperatures over 8 K.