  Understanding the mechanical properties of amorphous solids is a crucial area
of research due to the fascinating phenomena they exhibit under external
deformations and their importance in industrial applications. Although these
solids have higher yield strength compared to crystalline solids of similar
composition, they often fail catastrophically through shear band formation.
Tuning their mechanical behavior is vital for material design. Engineers have
long been seeking ways to improve the ability of amorphous solids to withstand
external deformations, with micro-alloying being a popular method. By adding
small amounts of different materials to pure samples, microalloying can enhance
yield strain, although the microscopic mechanisms behind this process remain
poorly understood. We conducted a study with extensive molecular dynamics
simulations on model amorphous solids to investigate the effect of asphericity
of the impurity particles on their yielding behaviour. Our results indicate
that aspherical impurities free to rotate can significantly increase the yield
threshold. Conversely, when impurities are unable to rotate, they can lead to
the formationof extremely brittle, ultrastable-like systems. The rotational
degrees of freedom are controlled bychanging the aspect ratio of the
impurity,and they play a crucial role in influencing shear bandformation.
Additionally, we found that including larger impurities enhances the structural
stabilityof the parent glass matrix.
