  The specific role of environmental interaction on bias driven circular
current in a ring nanojunction is explored, for the first time to the best of
our concern, within a tight-binding framework based on wave-guide theory. The
environmental interaction is implemented through disorder in backbone sites
where these sites are directly coupled to parent lattice sites of the ring via
single bonds. In absence of backbone disorder circular current becomes zero for
a lengthwise symmetric nanojunction, while it increases with disorder which is
quite unusual, and after reaching a maximum it eventually drops to zero in the
limit of high disorder. The effects of ring-electrode interface configuration,
ring-backbone coupling, different types of backbone disorder and system
temperature are critically investigated to make the present analysis
comprehensive. All the studied results are valid for a broad range of physical
parameters, giving us confidence that the outcomes of this theoretical work can
be verified in a laboratory.
