Multiferroic Double Perovskites <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mtext>ScFe</mml:mtext><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Cr</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>1</mml:mn><mml:mo stretchy="false">/</mml:mo><mml:mn>6</mml:mn><mml:mo>≤</mml:mo><mml:mi>x</mml:mi><mml:mo>≤</mml:mo><mml:mn>5</mml:mn><mml:mo stretchy="false">/</mml:mo><mml:mn>6</mml:mn></mml:math> ) for Highly Efficient Photovoltaics and Spintronics

Ferroelectric oxides are studied for applications in solar-energy conversion, but unfortunately most have a band gap of 3 eV or more and thus primarily absorb in the ultraviolet region, which is just 8% of sunlight. Lowering the band gap without spoiling the pivotal ferroelectric properties is a promising, challenging route to devices with meaningful power-conversion efficiency. The authors' calculations indicate that this goal can be realized in double perovskite ScFe${}_{1-x}$Cr${}_{x}$O${}_{3}$. Furthermore, the photocurrent it generates is predicted to be fully spin-polarized over nearly the entire solar spectrum, making this semiconductor intriguing for spintronics.