A new multi-node FLEET journal investigates the search for Majorana fermions in iron-based superconductors.
Majorana’s elusive fermion, or “angel particle” proposed by Ettore Majorana in 1937, behaves simultaneously as a particle and an antiparticle – and remains surprisingly stable rather than self-destructive.
Majorana’s fermions promise resistance-free information and communications technology, meeting the growing energy consumption of modern electronics (already 8% of global electricity consumption) and promising a sustainable future for computing.
Moreover, it is the presence of Majorana zero-energy modes in topological superconductors that has made these exotic quantum materials prime candidate materials for realizing topological quantum computing.
The existence of Majorana fermions in condensed matter systems will help FLEET research future low-power electronic technologies.
The angel particle: both matter and antimatter
Fundamental particles such as electrons, protons, neutrons, quarks and neutrinos (called fermions) each have their distinct antiparticles. An antiparticle has the same mass as its ordinary partner, but opposite electric charge and magnetic moment.
Conventional fermions and anti-fermions constitute matter and antimatter and annihilate when combined.
“Majorana’s fermion is the only exception to this rule, a composite particle that is its own antiparticle,” says corresponding author Professor Xiaolin Wang (UOW).
However, despite the intensive search for Majorana particles, the clue to its existence has been elusive for many decades, as the two contradictory properties (i.e. its positive and negative charge) render it neutral and its interactions with the environment are very weak.
Topological superconductors: fertile ground for the angel particle
Although the existence of the Majorana particle has not yet been discovered, despite extensive research at high-energy physics facilities such as CERN, it can exist as a single-particle excitation in systems condensed matter where band topology and superconductivity coexist.
“Over the past two decades, Majorana particles have been reported in numerous superconducting heterostructures and have been demonstrated with strong potential in quantum computing applications,” according to Dr. Muhammad Nadeem, FLEET postdoc at UOW.
A few years ago, a new type of material called iron-based topological superconductors was reported to harbor Majorana particles without fabrication of heterostructures, which is important for application in real devices.
“Our article reviews the most recent experimental achievements in these materials: how to obtain topological superconducting materials, the experimental observation of the topological state and the detection of Majorana zero modes”, explains Lina Sang, PhD candidate at the UOW.
In these systems, quasiparticles can mimic a particular type of Majorana fermion, such as the “chiral” Majorana fermion, one that moves along a one-dimensional path, and the Majorana “zero mode”, one that remains limited in a zero-dimensional space.
Majorana Zero Mode Applications
If such condensed matter systems, harboring Majorana fermions, are experimentally accessible and can be characterized by a simple technique, this would help researchers to guide the engineering of low-energy technologies whose functionalities are made possible by the exploitation unique physical characteristics of Majorana fermions, such as fault-tolerant topological quantum computing and ultra-low-energy electronics.
Accommodation of Majorana fermions in topological states of matter, topological insulators and Weyl semimetals will be covered at this month’s major International Conference on Semiconductor Physics (ICPS), which will be held in Sydney, Australia.
The IOP 2021 Quantum Materials Roadmap investigates the role of intrinsic spin-orbit coupling (SOC)-based quantum materials for Majorana mode-based topological devices, presenting evidence at the material boundary strong SOCs and superconductors, as well as in an iron-based system. superconductor.
The work is supported by the Australian Research Council’s Centers of Excellence, Future Fellowship and Discovery programs, and combined research across FLEET University Wollongong, RMIT University and UNSW, Sydney Nodes , as well as the partner organization of Tsinghua University (China).