  We explore the intriguing spatial patterns that emerge in a two-dimensional
spatially inhomogeneous Katz-Lebowitz-Spohn (KLS) driven lattice gas with
attractive nearest-neighbor interactions. The domain is split into two regions
with hopping rates governed by different temperatures T > T_c and T_c,
respectively, where T_c indicates the critical temperature for phase ordering,
and with the temperature boundaries oriented perpendicular to the drive. In the
hotter region, the system behaves like the (totally) asymmetric exclusion
processes (TASEP), and experiences particle blockage in front of the interface
to the critical region. To explain this particle density accumulation near the
interface, we have measured the steady-state current in the KLS model at T >
T_c and found it to decay as 1/T. In analogy with TASEP systems containing
"slow" bonds, we argue that transport in the high-temperature subsystem is
impeded by the lower current in the cooler region, which tends to set the
global stationary particle current value. This blockage is induced by the
extended particle clusters, growing logarithmically with system size, in the
critical region. We observe the density profiles in both high-and
low-temperature subsystems to be similar to the well-characterized coexistence
and maximal-current phases in (T)ASEP models with open boundary conditions,
which are respectively governed by hyperbolic and trigonometric tangent
functions. Yet if the lower temperature is set to T_c, we detect marked
fluctuation corrections to the mean-field density profiles, e.g., the
corresponding critical KLS power law density decay near the interfaces into the
cooler region.
