  In the presence of an obstacle, active particles condensate into a surface
"wetting" layer due to persistent motion. If the obstacle is asymmetric, a
rectification current arises in addition to wetting. Asymmetric geometries are
therefore commonly used to concentrate microorganisms like bacteria and sperms.
However, most studies neglect the fact that biological active matter is
diverse, composed of individuals with distinct self-propulsions. Using
simulations, we study a mixture of "fast" and "slow" active Brownian disks in
two dimensions interacting with large half-disk obstacles. With this
prototypical obstacle geometry, we analyze how the stationary collective
behavior depends on the degree of self-propulsion "diversity", defined as
proportional to the difference between the self-propulsion speeds, while
keeping the average self-propulsion speed fixed. A wetting layer rich in fast
particles arises. The rectification current is amplified by speed diversity due
to a superlinear dependence of rectification on self-propulsion speed, which
arises from cooperative effects. Thus, the total rectification current cannot
be obtained from an effective one-component active fluid with the same average
self-propulsion speed, highlighting the importance of considering diversity in
active matter. Finally, rectification alters particle evaporation and
absorption by the layer, making the density of the dilute phase increase with
the global density. Therefore, the steady state violates the lever rule, a
result which is valid even for systems of identical particles.
