 Nematic phases in frustrated magnets THESIS TOPIC PROPOSAL Institute: Budapest University of Technology and Economics physics Doctoral School of Physics Thesis supervisor: Karlo Penc belső konzulens: János Asbóth Location of studies (in Hungarian): Wigner Research Centre for Physics (WIGNER FK) Abbreviation of location of studies: BME Description of the research topic: Generally, the magnetic moment order in Mott insulators and a phase that breaks the time-reversal symmetry appears. However, there are theoretical proposals for time reversal invariant phases where the order parameter breaks the O(3) symmetry in the spin space. These are spin-nematic or spin quadrupolar phases. This may occur when both ferromagnetic and antiferromagnetic exchanges are present in a model, together with frustration, which leads to the formation of bound pairs of magnon excitations. The condensation of these bound pairs is then the spin-nematic phase. Using analytical and numerical methods, we will study the appearance of the bound pairs close to the ferromagnetic boundary in the triangular and face-centered cubic lattices and whether they can lead to nematic/quadrupolar phases for spin-1/2 and spin-1 systems. Required language skills: English Further requirements: The application of a student with good knowledge of math methods like group theory, linear algebra, quantum mechanics, numerical methods, and, most importantly, enthusiasm and interest in pursuing a challenging but rewarding problem is encouraged. Number of students who can be accepted: 1 Deadline for application: 2024-05-31 |