A few weeks ago, I just realized that it’s been already 2 years since I came to Germany and started research as a postdoc. It was quite surprising because I didn’t feel like so much time passed at all. I suppose it’s probably because last years was very special with the start of lockdown. Basically, working as a postdoc is not very different from my PhD time: I’m doing things on my own and I consut to my adivsors to hear opinion about if my idea would work or not. Slight difference would be that I feel like I am more trusted about what I am doing. It totally makes sense considering everything I learned during my PhD, which was essentially a course to be an independent researcher.
Regardless, I feel like I’m slowly moving toward a new direction. It’s still continuation of what I have done during my PhD though – orbitronics. But over the last year, I really thought hard about where the orbitronics research stands today and where we should go. I acknowledge discussions with many of my colleagues including my advisor. Anyway, I believe that we are very close to experimental discovery of the orbital Hall effect and orbital torque, which I proposed in the last years with real material examples. Not published yet (we’re missing “crucial” data that lead to logical conclusion), but these data are hardly explained without assuming the presence of the orbital current.
Many people might ask, if the orbital current is experimentally discovered, is this field over? No.
My conclusion is very simple. There must be plenty of physical phenomena which arise from the electronic orbital transport. We just need to find them. I think these are already implied in my previous papers. For example, in this paper, I discussed that interaction of the orbital and spin degrees of freedom with the environment, which essentialy constitues “external potential” for electronic systems, is the key. This is essentially lattice and magnetic order parameters and their excitations, phonon and magnons.
But as you would know well, doing physics is not only just coming up with fancy ideas. One has to be able to write down equations and calculate “numbers”: that’s exactly what the quantative science is for. That’s also why I had to spend quite a lot of time while the ideas were aleady around since the last year. For now, I can only say that I have a few ideas how to implement these ideas in equations and codes. But I don’t know whether my approaches would work or not. At the end I will definitely get some numbers but whether it matches with experiments is not guaranteed. Well, nobody really knows before trying. Despite all these, I have confidence from various circumstances (a.k.a. gut feelings obtained from known experimental results).
I really cannot wait to work further and see the result. This year is going to be quite interesting.