Fig. 2: Charge density wave on the (001) surface of CoSi.
From: Chirality locking charge density waves in a chiral crystal
a dI/dV map of a surface region with the stripe modulation taken under −6 mV. b 2D Brillouin zone of the surface withdrawn from the FT image of (a). The CDW spot is outlined by a red circle. c Normalized intensity profiles of the FT images along the blue dashed arrow in (b) under bias voltages from −30 mV to 30 mV. The intensity peaks around QCDW under different energies. The CDW wave vector is nondispersive with energy. d dI/dV maps of the region in (a) taken at 24 mV (upper panel) and −24 mV (lower panel). The bright stripes of the upper (lower) are outlined by red (black) dashed lines. e Typical dI/dV curves taken on (blue) and off (red) the bright stripes in Fig. 1b. Zero conductance for each spectrum is marked with a solid horizontal line. The blue arrows indicate two broad peaks in the spectra. The CDW gap 2ΔCDW is determined by the energy spacing between the left and right coherence peaks. f Temperature dependence of the CDW gap. The dI/dV sepctra are taken at a region different from that in Fig. 1b. Each curve is averaged from 10 independent dI/dV spectrum on the same bright stripe under different temperatures. The gap size gradually decreases with increasing temperature. g dI/dV map at 12 mV. h Gap map of the region in (g) acquired by recording the gap sizes at each pixel, showing a modulation of gap size by the CDW stripes.
