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Abstract
We report on experiments allowing to set an upper limit on the magnitude of the spin
Hall effect and the conductance by edge channels in quantum wells of PbTe embedded
between PbEuTe barriers. We reexamine previous data obtained for epitaxial microstructures
of n-type PbSe and PbTe, in which pronounced nonlocal effects and reproducible magnetoresistance
oscillations were found. Here we show that these effects are brought about by a quasi-periodic
network of threading dislocations adjacent to the BaF\(_2\) substrate, which give rise
to a p-type interfacial layer and an associated parasitic parallel conductance. We
then present results of transport measurements on microstructures of modulation doped
PbTe/(Pb,Eu)Te:Bi heterostructures for which the influence of parasitic parallel conductance
is minimized, and for which quantum Hall transport had been observed, on similar samples,
previously. These structures are of H-shaped geometry and they are patterned of 12
nm thick strained PbTe quantum wells embedded between Pb\(_{0.92}\)Eu\(_{0.08}\)Te barriers.
The structures have different lateral sizes corresponding to both diffusive and ballistic
electron transport in non-equivalent L valleys. For these structures no nonlocal resistance
is detected confirming that PbTe is a trivial insulator. The magnitude of spin Hall
angle gamma is estimated to be smaller than 0.02 for PbTe/PbEuTe microstructures in
the diffusive regime.