We calculate the local density of states of a two-dimensional electron systemunder strong crossed magnetic and electric fields. We assume a strongperpendicular magnetic field which, in the absence of in-plane electric fieldsand collision broadening effects, leads to Landau quantization and thewell-known singular Landau density of states. Unidirectional in-plane electricfields lead to a broadening of the delta-function-singularities of the Landaudensity of states. This results in position-dependent peaks of finite heightand width, which can be expressed in terms of the energy eigenfunctions. Thesepeaks become wider with increasing strength of the electric field and mayeventually overlap, which indicates the onset of inter-Landau-level scattering,if electron-impurity scattering is considered. We present analytical resultsfor two simple models and discuss their possible relevance for the breakdown ofthe integer quantized Hall effect. In addition, we consider a more realisticmodel for an incompressible stripe separating two compressible regions, inwhich nearly perfect screening pins adjacent Landau levels to theelectrochemical potential. We also discuss the effect of an imposed current onthe local density of states in the stripe region.
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