The physics of topologically nontrivial quantum materials originated in the last 15 years, and now it is one of the most rapidly developing areas in the new quantum “revolution”. The main object of study is the “topologically protected” quantum states of electrons freely propagating along the surface or along the edges. Their spin is rigidly tied to the direction of the pulse. These states arise on the surface of quantum materials: topological insulators (TI), Weyl and Dirac semimetals (WSM, DSM).
Since the creation of quantum mechanics in the early 20th century quantum physics has not experienced such rapid development. One of the reasons for the huge interest of researchers in this field is related to the prospect of creating fundamentally new types of devices for spintronics and quantum computing based on protected quantum states. Currently, the main obstacle to the use of quantum computing is the loss of coherence of quasiparticles (for simplicity, electrons) due to environmental influences. Topologically protected quantum states, including Majorana fermions, being resistant to external disturbances provide a way to solve this problem. Another reason is connected with the possibility of implementing exotic elementary particles — Majorana fermions, Higgs bosons, etc. in nanostructures based on TI, superconductors (SC) and WSM. These particles have been trying to detect for a long time (or are being detected at a huge cost) in experiments on accelerators. Finally, heterostructures based on SC and TI make it possible to construct a band spectrum of electrons with a huge density of states at the Fermi level (the so-called “flat zones”), creating prerequisites for a sharp increase in the critical temperature of superconductivity.