Majorana fermions are particles which are their own anti-particles. They were first hypothesized by Ettore Majorana in 1937. It is still unclear if there are elementary particles which are MFs. But in certain condensed matter systems, they are likely to exist as quasiparticle excitations. The condensed matter version of MFs have attracted a lot of interest, mainly because they obey non-abelian statistics and thus can be used as the building block of a topological quantum computer.
1D nanowire proposal
Based on the proposals by Lutchyn et al, and Oreg et al, the requirements to create Majorana fermions are greatly simplified to basically four ingredients, which are :
- One-dimensional nanowire
- Spin-orbit interaction
- Induced Superconductivity
- Magnetic field
In our experiment, we used InSb nanowire which has strong spin-orbit coupling and large g factor. NbTiN is used as the parent superconductor due to its high critical magnetic field. We used bottom gates to tune the chemical potential of the nanowire to achieve topological phase condition and all the measurement was done in a dilution fridge with a base temperature around 20mK.