Macroscopic Quantum Tunneling of a Topological Ferromagnet
arXiv:2206.03972 · doi:10.1002/advs.202303165
Abstract
The recent advent of topological states of matter spawned many significant discoveries. The quantum anomalous Hall effect[1-3] is a prime example due to its potential for applications in quantum metrology[4, 5] as well as its influence on fundamental research into the underlying topological and magnetic states[6-11] and axion electrodynamics[2, 12-14]. Here, we perform electronic transport studies on a (V,Bi,Sb)2Te3 ferromagnetic topological insulator nanostructure in the quantum anomalous Hall regime. This allows us access to the dynamics of an individual ferromagnetic domain. The volume of the domain is estimated to be about 85 000 nm3, containing some 50 000 vanadium atoms, spread over a macroscopic distance of 115 nm. Telegraph noise resulting from the magnetization fluctuations of this domain is observed in the Hall signal. Careful analysis of the influence of temperature and external magnetic field on the domain switching statistics provides evidence for quantum tunneling of magnetization[15-22] in a macrospin state. This ferromagnetic macrospin is not only the largest magnetic object in which quantum tunneling has been observed, but also the first observation of the effect in a topological state of matter.
References in corpus (10)
- Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
- Quantum Spin Hall Insulator State in HgTe Quantum Wells
- Quantized Anomalous Hall Effect in Magnetic Topological Insulators
- Finite size effects of helical edge states in HgTe/CdTe quantum wells
- Surface quantized anomalous Hall current and magneto-electric effect in magnetically disordered topological insulators
- Scaling of the Quantum Anomalous Hall Effect as an Indicator of Axion Electrodynamics
- Any Axion Insulator Must be a Bulk Three-Dimensional Topological Insulator
- Quantum anomalous Hall edge channels survive up to the Curie temperature
- Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators
- Macroscopic Quantum Tunneling of a Topological Ferromagnet