Scientists have recorded strange behavior of electrons in the quantum material zirconium pentatelluride (ZrTe5). At conditions close to absolute zero and in magnetic fields up to 60 tesla, the material exhibits quantum oscillations that do not disappear where standard theory requires them to.
Ordinary magnetoresistance oscillations are periodic in the inverse field and decay beyond the quantum limit. In ZrTe5, the pattern is different: oscillations continue further than expected and do not follow the usual periodicity of 1/B.
Experiments were conducted at temperatures around 0,7 kelvin. The team combined electrical transport measurements in ultrahigh fields with detailed theoretical calculations.
The study was led by specialists from the University of São Paulo in Brazil, together with colleagues from Los Alamos National Laboratory and the University of Washington. The results were published in Nature Communications.
Professor Julio Larrea Jiménez from USP notes that the work expands the understanding of electron transport in exotic phases of matter. Topological insulators, he says, can carry not only charge but also the spin of electrons.
In materials near topological phase transitions, electrons behave like quasiparticles similar to relativistic Dirac fermions. The interaction of their spin with the magnetic field changes the energy levels so that Landau levels 'return' and cross the relevant energy of the system again.
This observation points to a topological origin of the effect, rather than ordinary many-body interactions. What lies behind such persistence of oscillations?
The discovery highlights the role of spin in the transport properties of topological materials and opens the way to a deeper understanding of quantum phases under extreme conditions.
