Giant Bulk Photovoltaic Effect in Penta-PdTe₂ Induced by Layer Stacking

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Stacking engineering is a key method for tailoring layered material properties.
• Recent synthesis of penta-PdTe2 sheets provides a new material for study.

Purpose of the Study:

• To investigate the polarization and bulk photovoltaic effect of bilayer penta-PdTe2.
• To compare the photovoltaic response of penta-PdTe2 with penta-PdSe2 and penta-PdS2.

Main Methods:

• Symmetry analysis and first-principles calculations were employed.
• Analysis included transition intensity, shift vector distributions, and charge transfer.

Main Results:

• Bilayer penta-PdTe2 shows significant in-plane polarization with a spontaneous polarization of 1.70 × 10^-10 C m^-1.
• A giant shift current of 125.49 μA V^-2 was observed, exceeding that of penta-PdSe2 and penta-PdS2.
• The mechanism involves transition intensity, shift vector distribution, and charge transfer in X dimers.

Conclusions:

• Pentagonal materials are a promising platform for developing polar materials.
• Strong bulk photovoltaic effects can be achieved in these engineered materials.