CHARGE-DENSITY-WAVE MODIFICATIONS IN NBSE3 PRODUCED BY FE AND CO DOPING

Dilute concentrations of impurities in NbSe3 crystals change the charge-density-wave (CDW) energy gaps very rapidly while the onset temperatures show very small changes. Fe concentrations of < 1% reduce the two CDW energy gaps by approximately 30% while Co concentrations of < 3% increase the low-temperature CDW energy gap by approximately 37% and the high-temperature CDW gap by approximately 28%. The real-space scanning-tunneling-microscope scans show changes in the relative CDW modulation amplitudes consistent with the observed changes in the energy gaps.