Correlated Oxide Dirac Semimetal in the Qantum Limit*

Quantum materials with strong correlation and non-trivial topology are indispensable to next-generation technologies. Exploitation of topological band structure is an ideal starting point to realize correlated topological QMs. In this talk, I will introduce recent discovery of strain-induced correlated topological phase in strained SrNbO₃ films. Dirac electrons in strained SrNbO₃ films revealed ultra-high mobility (μ_max ≈ 100,000 cm²/Vs), exceptionally small effective mass (m* ~ 0.04m_e), and non-zero Berry phase. More importantly, strained SrNbO₃ films reached the extreme quantum limit, exhibiting a sign of fractional quantum states and giant mass enhancement. Our results suggest that symmetry modified SrNbO₃ is a rare example of correlated topological QMs, in which strong correlation of Dirac electrons led the realization of fractional occupation of Landau levels