A pinboard by
Jorge Puebla

Postdoctoral researcher, RIKEN


Spin to electrical charge conversion at light – voltage - mechanic interactions

The global urge for finding new means for saving energy has already led to important technology advances in recent years, such as solar cells based on perovskite structures which drastically enhanced their conversion efficiency (2009 efficiency 3.8%, 2016 efficiency 22.1%) at relatively low production costs. Analogous, energy harvesting technology through piezoelectric effect have gained much attention in recent times, with many proposal for the so-called “smart cities” which convert otherwise wasted vibration energy into useable electrical energy to charge batteries and capacitors. Start – up companies are emerging rapidly with different innovative proposals based on these recent technology advancements, among others such as Seebeck effect to convert thermal energy into electrical currents. In terms of fundamental research, the energy conversion processes also open up intriguing opportunities particularly at the nanoscale. Hence, the spin degree of freedom of electrons can act as an intermediate rectifier for conversion phenomena among electricity, light, sound, vibrations, and heat. Several research groups worldwide are currently very active on these topics, with some initiatives that bring together an interesting mix of collaborators. Myself, currently I belong to a research group in Japan that has been part of one of these initiatives, “The nano spin conversion science”. As part of this research group, I have devoted my efforts to develop the experimental techniques and devices to explore the interconversion between light – voltage and mechanics – voltage, through the assistance of transfer of angular momentum (spin). Recently, we succeeded to generate and detect photovoltaic conversion with spin dependence, at interfaces with spin orbit interaction. Also, we succeeded to generate and detect spin to electrical charge conversion mediated by surface acoustic waves propagating at ferromagnetic / nonmagnetic metal / oxide trilayers. These results tested the feasibility of our project and motivate further exploring in-coming energy efficient device applications.