Scanning tunneling microscopy of orthorhombic TaS3

Scanning-tunneling-microscopy studies of orthorhombic ${\mathrm{TaS}}_3$ at 77 K show a charge-density modulation of wavelength 4${\mathrm{c}}_0$ strongly localized on two separate pairs of chains. The charge maxima are out of phase and suggest a strong coupling between the two charge modulations.