A van der Waals interface that creates in-plane polarization and a spontaneous photovoltaic effect

Van der Waals interfaces can be formed by layer stacking without regard to lattice constants or symmetries of individual building blocks. We engineered the symmetry of a van der Waals interface of tungsten selenide and black phosphorus and realized in-plane electronic polarization that led to the emergence of a spontaneous photovoltaic effect. Spontaneous photocurrent was observed along the polar direction and was absent in the direction perpendicular to it. The observed spontaneous photocurrent was explained by a quantum-mechanical shift current that reflects the geometrical and topological electronic nature of this emergent interface. The present results offer a simple guideline for symmetry engineering that is applicable to a variety of van der Waals interfaces.

Source: ScienceNOW - April 1, 2021 Category: Science Authors: Akamatsu, T., Ideue, T., Zhou, L., Dong, Y., Kitamura, S., Yoshii, M., Yang, D., Onga, M., Nakagawa, Y., Watanabe, K., Taniguchi, T., Laurienzo, J., Huang, J., Ye, Z., Morimoto, T., Yuan, H., Iwasa, Y. Tags: Materials Science, Physics reports Source Type: news