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Switchable magnetic bulk photovoltaic effect in the two-dimensional antiferromagnet CrI3

Pátek, 31.01.2020 14:00

Přednášející: Yang Zhang (Massachusetts Institute of Technology)
Místo: Velká zasedačka, budova A (naproti knihovně) FzÚ AVČR, Cukrovarnická 10, Praha 6
Jazyk: angličtina
Pořadatelé: Oddělení spintroniky a nanoelektroniky

The bulk photovoltaic effect (BPVE) rectifies light into the dc current in a single-phase material and attracts the interest to design high-efficiency solar cells beyond the pn junction paradigm. Because it is a hot electron effect, the BPVE surpasses the thermodynamic Shockley–Queisser limit to generate above-band-gap photovoltage. While the guiding principle for BPVE materials is to break the crystal centrosymmetry, here we propose a magnetic photogalvanic effect (MPGE) that introduces the magnetism as a key ingredient and induces a giant BPVE. The MPGE emerges from the magnetism-induced asymmetry of the carrier velocity in the band structure. We demonstrate the MPGE in a layered magnetic insulator CrI3 , with much larger photoconductivity than any previously reported results. The photocurrent can be reversed and switched by controllable magnetic transitions. Our work paves a pathway to search for magnetic photovoltaic materials and to design switchable devices combining magnetic, electronic, and optical functionalities.