Figure 4: Variation in the energy gap distribution in different MgB2 junctions.
From: Momentum-dependent multiple gaps in magnesium diboride probed by electron tunnelling spectroscopy
(a) The energy gap distributions for four junctions: A (black), B (red), C (Green) on MgO (211) and D (blue) on c-axis-8°-tilted SiC. Each curve is normalized to its peak value and shifted vertically for clarity. Curves for junctions A and C were obtained at T=1.8 K and those for junctions B and D were obtained at T=4.2 K. The values of the product RnA are 1.6, 0.82, 7.7 and 2.6 mΩcm2 for junctions A, B, C and D, respectively. The σ-gap curve for junction D is magnified five times. (b) The energy gap distribution around π gap region for 4 junctions on SiC (0001) substrates at T=4.2 K with different N2 flow rates during the MgB2 growth. (inset) The dependence of FWHM of the gap distribution peaks and the electron mean free path (MFP) to the flow rate of N2 addition.
