Strain-tuned topological phase transition and unconventional Zeeman effect in ZrTe5 microcrystals

Band structure modulation may drive topological phase transitions, but tuning topological phases within the same material is challenging. Here, quantum oscillations are used to map the Berry phase and Dirac bandgap closing and reopening in a strain-induced topological insulator phase transition in ZrTe5. The geometric phase of an electronic wave function, also known as Berry phase, is the fundamental basis of the topological properties in solids. This phase can be tuned by modulating the band structure of a material, providing a way to drive a topological phase transition. However, despite significant efforts in designing and understanding topological materials, it remains still challenging to tune a given material across different topological phases while tracing the impact of the Berry phase on its quantum transport properties. Here, we report these two effects in a magnetotransport study of ZrTe5. By tuning the band structure with uniaxial strain, we use quantum oscillations to directly map a weak-to-strong topological insulator phase transition through a gapless Dirac semimetal phase. Moreover, we demonstrate the impact of the strain-tunable spin-dependent Berry phase on the Zeeman effect through the amplitude of the quantum oscillations. We show that such a spin-dependent Berry phase, largely neglected in solid-state systems, is critical in modeling quantum oscillations in Dirac bands of topological materials.

Automated summary

Band structure modulation can drive topological phase transitions, with the Berry phase and Dirac bandgap closing and reopening in ZrTe5 strain-induced topological insulator phase transition directly mapped using quantum oscillations. The impact of strain-tunable spin-dependent Berry phase on the Zeeman effect through quantum oscillation amplitude is critical in modeling quantum oscillations in Dirac bands in topological materials.