The history of information technology is deeply tied to how we manipulate one of the fundamental parts of the atom: the electron. Early on, engineers learned to move the electron’s negative charge through materials, which was used to create electrical currents and store energy through charge accumulation. This control over electrons became the foundation of most devices we use today. (Here, “electronics” comes from “electron,” and “electrical current” means electrons moving together.)
Later, exploiting another property of electrons — their spin — led to new advances. (For a deeper dive into the history and details of spintronics, see Mayank’s excellent post.)
The spin of electrons is a complex concept. Still, macroscopically, it can be thought of as an intrinsic identity of the electron, like a color (red or blue) or an arrow (up or down). It gives rise to a tiny magnetic field per electron. By learning to control the spin, we opened the door to a new field called spintronics, where devices manipulate spin currents (electrons with a particular spin moving together) and spin accumulation (electrons with a specific spin gathering in one place).
Of course, this is only a small part of the whole story. The spin is not the only property we can exploit. From the fundamentals of quantum mechanics, we know that an electron’s total angular momentum combines spin and orbital angular momentum — the latter arising from the complex, cloud-like paths that electrons trace as they move along the system and around the centers of atoms. These orbital motions create an additional magnetic moment, meaning electrons can carry magnetism from their spin and orbital motion.” This leads us to a second new set of names: orbitronics, orbital currents, and orbital accumulation.
We can imagine an orbital current as a collective movement of electrons that rotate similarly as they move through a crystal (see the video above).
However, detecting orbital accumulation — where orbital angular momentum builds up at material edges — is not as straightforward. It remains a topic of active discussion within the scientific community.
For instance, during the recent SPEAR conference (Spin and Orbit in San Sebastián), leading researchers gathered to discuss the state of the art in orbitronics and the major experimental and theoretical challenges ahead.
If spintronics opens the door to new ways of using electrons, then orbitronics opens an additional window to even greater possibilities. Spintronics and orbitronics are deeply intertwined, so separating the effects of spin and orbital currents in many experiments is exceptionally challenging.
This is where my own research comes in.
I study charge-to-spin and orbital conversion — how an incoming electrical current can be transformed into spin and orbital currents. They have to be produced somehow by answering key questions — how, why, how much, and under what conditions — we can identify promising materials that maximize useful effects while minimizing cost and complexity.
Physics is endlessly fascinating on its own, but at some point, our work must also aim toward practical goals: making future devices faster, cheaper, more energy-efficient, and more environmentally friendly.
Despite the current uncertainties, the future of orbitronics is bright. Mastering the orbital degree of freedom is part of a much larger trend: learning to control the hidden properties of electrons and materials.
Under the growing umbrella of “X-Tronics,” fields like:
– Valleytronics (controlling electrons based on energy valleys),
– Twistronics (tuning properties by twisting atomic layers),
– Phononics (managing atomic vibrations),
are rapidly expanding.
The next technological revolution might not be about moving more electrons — but about moving them smarter and more efficiently.
