Magnetotransport measurements through stacked InAs self-assembled quantum dots

We report on low temperature magnetotunneling measurements through an AlAs/GaAs n-i-n diode incorporating stacked double layers of InAs self-assembled quantum dots (SAQDs). We observe that two strong conductance peaks at zero magnetic field (B) are split into four peaks at high B values. The double conductance peaks are interpreted as due to the conduction through the symmetric and antisymmetric states of coupled SAQDs. The separations between conductance peaks at B=0 and at B=18 T are consistent with the calculated energy separation between the symmetric and the antisymmetric states and with the previously reported Zeeman splitting, respectively.