Enhancing the shear strength of single-crystalline In4Se3 through point defects

The intrinsic shear strength (1.25 GPa) of In 4 Se 3 remarkably lower than those of classic thermoelectric (TE) materials such as CoSb 3 (7.17 GPa), PbTe (3.46 GPa), TiNiSn (10.52 GPa), which limits the commercial applications of In 4 Se 3 based TE materials. To improve the shear strength of single-crystalline In 4 Se 3 , we used density functional theory to study the influence of point defects on the mechanical behavior of In 4 Se 3 under the pure shear loading. We found that doping with Ca, Ag, Yb, Pb, Zn, I, and Br can improve the shear strength of In 4 Se 3 . In particular, Ca-doped In 4 Se 3 obtained the highest shear strength (1.43 GPa), an increase of 14.4%. These point defects can improve the van der Waals interaction between In/Se layers significantly, hence enhancing the shear strength, while the slippage between the In/Se layers is still predominating its deformation and failure. Our work offers a possibility in strengthening layered materials with robust mechanical properties .