ELECTRON GLASS - INTERVALLEY TRANSITIONS AND THE HOPPING CONDUCTION NOISE

The properties of the electron glass ground state and of those low-ene rgy metastable states (valleys), in which the Coulomb potential at any occupied impurity is lower than that at any empty one, are studied by computer simulation. The transitions between just these states are ex pected to determine the low-frequency stochastic dynamics of the elect ron glass at low temperatures. The variation of the number of valleys, N-v, in samples with the same number of impurities, N-D, but differen t arrangements, the shift of the N-v distribution to greater numbers w ith growing N-,N- the energy range of the valleys, the differences bet ween the electron arrangements in different valleys in the same sample , and the activation energies for intervalley transitions are found. T he energy range of the valleys is, at any N-D, on the order of the cha racteristic Coulomb energy at the mean distance between impurities. Si nce the number of valleys grows with N-D the mean distance between adj acent valley energies drops with N-D. Despite the small differences be tween the valley energies the valleys are separated by energy barriers that, in samples with high number of N-D and N-v, are distributed wit hin a wide range. The width of this range grows with the size of the s ample (N-D) and with the number of valleys in it. This is an argument in favor of the idea that just the intervalley transitions are the sou rce of low-frequency hopping conduction noise with the 1/f spectrum in lightly doped semiconductors at low temperatures. [S0163-1829(98)0561 6-1].