Extended Data Fig. 7: Gap modulation on device #2.
From: Cooper-pair density modulation state in an iron-based superconductor
a, Optical image of device #2. Inset, AFM line profile measured along the dashed white line in b, showing the thickness of the flake (30 nm). b, AFM image of device #2. c, SC gap map on a 1.7 × 1.7-nm2 area. Inset, the FT magnitude of the SC gap map. d, The STM topography acquired simultaneously with the gap map in c. The white circles mark the positions of gap maxima appearing at the Fey sites. e–j, dI/dV linecuts measured on device #2 along either the x axis or the y axis. The average gaps are \(\bar{\Delta }=1.30,\,2.00,\,2.09,\,2.03,\,1.60\,{\rm{and}}\,1.76\,{\rm{meV}}\) and the PDM modulation amplitudes are |ΔP| = 0.40, 0.50, 0.61, 0.69, 0.56 and 0.72 meV for each corresponding linecut. The average modulation ratio is 35% in this device, with individual ratios being 31%, 40%, 29%, 34%, 35% and 41%, respectively. Set points: Vbias = −5 mV, It = 700 pA for e, 1.3 nA for (c,d,f), 1.5 nA for g–i.
