Press Releases


A van der Waals interface that creates in-plane polarization and a spontaneous photovoltaic effect : Assistant Professor Toshiya Ideue, Quantum - Phase Electronics Center, Takatoshi Akamatsu(M2), Yu Dong, Assistant Professor Sota Kitamura(M2), Mao Yoshii(M2), Doctoral Course Masaru Onga, Doctoral Course Yuji Nakagawa, Associate Professor Takahiro Morimoto, Professor Yoshihiro Iwasa, Department of Applied Physics, and other researchers.

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.

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