The Arctic Ocean main thermocline may be characterized by a series of fine-scale thermohaline staircase structures that are present in a wide range of regions, the formation mechanism of which remains unclear. Recent analysis has led to the proposal of a theoretical model which suggested that these staircase structures form spontaneously in the salinity and temperature-stratified ocean when the turbulent intensity determined by the buoyancy Reynolds number Reb is sufficiently weak (Ma and Peltier (2021)). In the current work, we have designed a series of Reb controlled direct numerical simulations of turbulence in the Arctic Ocean thermocline to test the effectiveness of this theory. In these simulations, the staircases form naturally when Reb falls in the range predicted by the instability criterion that is the basis of the proposed theory. In the DNS analyses described we show that the exponential growth-rate of the layering mode of instability matches well with the prediction of (Ma and Peltier (2021)). The staircases formed in our simulations are further compared with the classical diffusive interface model initially proposed by (Linden and Schirtcliff (1978)), which argued that stable staircase structures can only form when the density ratio Rρ is smaller than the critical value Rρ^{cr}=τ^(-1/2). . We show that the staircase structures can stably persist in the model regardless of whether or not Rρ is satisfied because of the involvement of stratified turbulence in the interfaces of the staircase.