  Dust trapping in the global pressure bump induced by magnetospheric
truncation offers a promising formation mechanism for close-in
super-Earths/sub-Neptunes. These planets likely form in evolved protoplanetary
discs, where the gas temperature at the expanding truncation radius become
amiable to refractory solids. However, dust accumulation may alter the disc
opacity such that thermal evolution is inevitable. To better understand how
thermodynamics affects this planet formation pathway, we conduct a suite of
local dust evolution simulations in an idealized inner disc model. Our
calculations take into account self-consistent opacity-dependent temperature
changes as well as dust evaporation and vapour condensation. We find that disc
thermal evolution regulates dust growth and evolution, discouraging any
accumulation of small particles that drives the increase of opacity and
temperature. Significant retention of dust mass takes place when the disc
environments allow runaway growth of large solids beyond the fragmentation
barrier, where small particles are then swept up and preserved. Our results
further validate dust accumulation near disc truncation as a promising
mechanism to form close-in planets.
