SKM 2023 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 10: Topological Insulators (joint session MA/TT)
MA 10.5: Vortrag
Montag, 27. März 2023, 16:15–16:30, HSZ 403
Investigation of the magnetic topological insulator family (MnPn2Te4) (Pn2Te3) n, (Pn=Bi, Sb) by μSR and NMR — •Manaswini Sahoo1,2, Anna Isaeva1, Bernd Büchner1, and Roberto De Renzi2 — 1Leibniz IFW Dresden, Dresden, Germany — 2University of Parma,Parma, Italy
Time-reversal symmetry breaking in a topological insulator (TI) opens a surface gap and distinguishes chiral quantum states that could eventually be exploited in electrically controlled spintronic devices. The recent discovery of layered van der Waals materials opens a new approach to achieve this.(MnBi2Te4) (Bi2Te3) n is one of the first such examples, where the increasing number n of TI layers controls the magnetic dimensionality of the material. These compounds do display the quantum anomalous Hall effect, where spontaneous magnetization and spin-orbit coupling lead to a topologically non-trivial electronic structure. In the case of (MnBi2Te4) (Bi2Te3) n, Zero Field μSR shows more than one internal field at the muon site with the majority one decreasing in value when n is increased. The muon spin precessions display very fast relaxations of static inhomogeneous nature. Whereas in the sister compound MnSb2Te4, Zero Field μSR shows a broader distribution of magnetic field at the muon due to larger intermixing between Mn/Sb in the sample. Importantly, the weak Transverse Field shows a sharp magnetic transition at the same Tc, with a clear relaxation peak due to critical fluctuations, taking place in the whole volume of the material. This local information from μSR together with NMR is crucial to correctly interpret macroscopic magnetization data.