  Janus nanoparticles (JNPs) with heterogeneous compositions or interfacial
properties can exhibit directional heating upon external excitation, such as
laser radiation and magnetic field. This directional heating may be harnessed
for new nanotechnology and biomedical applications. Understanding thermal
transport and temperature control with JNP heating is critical for these
advances. Here, we developed a numerical framework to analyze the asymmetric
thermal transport in JNP heating under photothermal stimulation. We found that
JNP-induced temperature contrast, defined as the ratio of temperature increase
in the surrounding water, shows a substantial size and polar angle dependence.
Notably, we discovered a significant enhancement of the temperature contrast
under pulsed heating due to thermal confinement, compared with the continuous
heating. This work brings new insights into the thermal responses of JNP
heating and advances the field.
