Scaling behavior studies of Ar+ ion irradiated ripple structured mica surfaces

We have studied scaling behavior of ripple structured mica surfaces. Clean mica (001) surface is sputtered by 500 eV Ar+ ion beam at 40° incidence angle for different time ranging from 28 minutes to 245 minutes to form ripples on it. The scaling of roughness of sputtered surface characterized by AFM is observed into two regime here; one is super roughening which is for above the crossover bombardment time (i.e, tx ≥ 105 min) with the scaling exponents α = αs = 1.45 ± 0.03, αlocal = 0.87 ± 0.03, β = 1.81 ± 0.01, βlocal = 1.67 ± 0.07 and another is a new type of scaling dynamics for tx ≤ 105 min with the scaling exponents α = 0.95 (calculated), αs = 1.45 ± 0.03, αlocal = 0.87 ± 0.03, β = 1.81 ± 0.01, βlocal = 1.67 ± 0.07. In the super roughening scaling dynamics, two types of power law dependency is observed on spatial frequency of morphology (k): for higher k values PSD ∼ k−4 describing diffusion controlled smoothening and for lower k values PSD ∼ k−2 reflecting kinetic roughening