Professor’s Work Highlighted by the Department of Energy

Madhab Neupane, Ph.D., an assistant professor in the Department of Physics, uses light to eject electrons out of materials revealing the states of electrons occupy inside the material. He does so by using a technique known as angle-resolved photoemission spectroscopy (ARPES). He employs very intense (but finely controlled) light beams to illuminate a sample, extract electrons, and then measure the energy and momentum of these electrons. With the aid of state-of-the-art technologies, the state of the electrons can be reconstructed as they were inside the sample providing advanced insight into the fundamental properties of the material.

In his work, Neupane and collaborators are the first to provide direct evidence that BiPd, a noncentrosymmetric (NCS) material, exhibits spin polarized surface states. This is a similar property found within topological insulators – a promising class of solids that conducts electricity on its surface but resists it through its interior. The existence of spin-polarized surface states in the NCS material BiPd, provides unique insight into the electronic structure and identifies a potential pathway to the elusive Majorana fermion surface states for quantum computation.

Quantum computation is a novel way to process information that promises to be much more efficient (namely, faster) than current technologies. However, most quantum computer technologies explored so far are very prone to errors because of the fragility of quantum information (it tends to get washed away very quickly by all sorts of background noise. It is recently proposed that topological superconductors can be used to implement a new form of quantum computing that is noise tolerant and error proof. Technically, these materials can be used to implement the so-called “Majorana fermions”, which are hard to explain, but pictorially you can think of them as fictitious particles that, when put together, care about nothing, therefore preserving their quantum state for long times.

Neupane’s latest results provide vital insight into the origin of superconductivity and the detection of Majorana fermions at Dirac points on the surface compared to the bulk. Ultimately, this result may help to identify Majorana fermions. These particles could revolutionize the development of quantum computers.

This work has published in Nature Communications and highlighted by the U.S. Department of Energy, Basic Energy Science.