2/28/2023 0 Comments Element zero mass effect 2The existence of Majorana fermions has been intensely explored. This result is impressive if we recall that we're talking about a Mott insulator for which the electron charges are frozen and which therefore cannot transport electrical current." In effect, the topological phase is characterized by the presence, at the edge of the system, of Majorana fermions that carry a quantized energy current. "Our work provided a consistent framework for experiments involving disordered Kitaev spin liquids and also produced an important prediction: this material should exhibit a topological phase in the presence of an external magnetic field. Because hydrogen is a very light element, these defects are expected to appear in the system during the crystallization process," Andrade said. The vacancies correspond to replacement of the magnetic ion by a non-magnetic ion. We showed that the presence of a small number of vacancies was sufficient to explain the experimental data. "We succeeded in explaining the contradictions between the predictions of the pure Kitaev model and the experimental results obtained with H 3LiIr 2O 6. This Mott insulator shows no magnetic order down to 50 millikelvin, making it a prominent candidate to realize Kitaev's spin-liquid phase. The study reported by Andrade and Dantas focused on an iridium oxide, H 3LiIr 2O 6. For this reason, Kitaev materials usually involve iridium and ruthenium ," Andrade said. A prerequisite for the relevance of this term is that the system's magnetic atom has a very high atomic number. "This is essential to create magnetic Kitaev interactions. This effect couples the electron's spin with its movement in three-dimensional space. Spin-orbit coupling is a manifestation of restricted relativity in atomic and condensed matter systems. The only contribution came from spin," Andrade said. "In this study, the electrons were frozen in space, as it were, so that their mass and charge didn't participate in the dynamics at low temperatures. Scientists are very interested in them because of the possibility of accessing electron charge and spin separately, which gives rise to a wealth of unique physical properties, such as those of spin liquids. Mott insulators are complex materials that act as electrical insulators but have spin dynamics and behave like magnetic materials. "Since 2009, there have been robust theoretical proposals that the model can be realized in Mott insulators, which exhibit strong spin-orbit coupling," Andrade said. research he supervises, studied how Kitaev's model behaves in a honeycomb lattice in the presence of defects and disturbances such as a magnetic field and additional interactions. Andrade is a professor at the University of São Paulo's São Carlos Institute of Physics (IFSC-USP) in Brazil.Īndrade and Vitor Dantas, whose Ph.D. Deviations from the original model are expected to appear in real materials and that is what we investigated," Eric Andrade, last author of the article, told Agência FAPESP. It's very interesting but somewhat artificial. "The Kitaev model is a two-dimensional spin liquid. An example is the article "Disorder, low-energy excitations, and topology in the Kitaev spin liquid" published in Physical Review Letters. A considerable research effort is under way in the field for this very reason. In accordance with the same logic, a system with magnetic order is a spin solid, since the magnetic order of its spins is analogous to the periodic order of the atoms in a crystal.Įxploration of these systems helps scientists understand fundamental aspects of matter and could lead eventually to an important practical application-topological quantum computing. By analogy with usual liquids, a system in which spins do not exhibit magnetic order, even at temperatures close to absolute zero, is termed a spin liquid.
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