Here we can see how parts of a curve can be emphasized. A color shading partitions the plane.
The code is from a question by lorbj on TeXwelt.de http://texwelt.de/wissen/fragen/9875/numerisches-problem-mit-pgfplots and from the answer by Elke Schubert.
Edit and compile if you like:\documentclass[border=10pt]{standalone}\usepackage{pgfplots}\pgfplotsset{compat=1.10}\begin{document}\begin{tikzpicture}\begin{axis}[domain = 0.97:2.3,samples = 100,% <- nur 100 statt 400xmin = 0.8,xmax = 2.3,ymin = -0.3,ymax = 0.3,ytick = \empty,xtick = \empty,xlabel = {Abstand [a.u.]},ylabel = {Kraft [a.u.]},extra y ticks = {0},xlabel near ticks,ylabel near ticks,set layers,]\begin{pgfonlayer}{axis background}\fill[shade, top color=blue!0, bottom color=blue!25](rel axis cs:0,0)--(rel axis cs:1,0)--(rel axis cs:1,0.5)--(rel axis cs:0,0.5)--cycle;\fill[shade, top color=red!25, bottom color=red!0](rel axis cs:0,0.5)--(rel axis cs:1,0.5)--(rel axis cs:1,1)--(rel axis cs:0,1)--cycle;\end{pgfonlayer}\addplot[line width=5pt,color = green!50, domain = 1.05:1.25]{1/x^12-1/x^6};\addplot[line width=5pt,color = blue!50, domain = 0.98:0.992]{1/x^12-1/x^6};\addplot[thick,samples=400% 400 für die Gesamtkurve] {1/x^12-1/x^6};\node[anchor= north] at (axis cs: 1.122462048,-0.26) {$r_0$};\draw[dashed,thin] (axis cs: 0.8, 0 )-- (axis cs: 2.3, 0);\node[anchor = north] at (rel axis cs:0.75,0.75) {repulsiv};\node[anchor = south] at (rel axis cs:0.75,0.25) {attraktiv};\end{axis}\end{tikzpicture}\end{document}