Avoided level crossing at the magnetic field induced topological phase transition due to spin-orbital mixing

Abstract

In 3D topological insulators, an effective closure of the bulk energy gap with increasing magnetic field expected at a critical point can yield a band crossing at a gapless Dirac node. Using high-field magnetooptical Landau level spectroscopy on the topological crystalline insulator Pb1-xSnxSe, we demonstrate that such a gap closure does not occur, and an avoided crossing is observed as the magnetic field is swept through the critical field. We attribute this anticrossing to orbital parity and spin mixing of the N=0 levels. Concurrently, we observe no gap closure at the topological phase transition versus temperature suggesting that the anticrossing is a generic property of topological phase transitions.

arXiv commentsubmitted

References in corpus (18)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Crystalline Insulators in the SnTe Material Class
• Observation of a topological 3D Dirac semimetal phase in high-mobility Cd3As2
• Topological crystalline insulator states in Pb(1-x)Sn(x)Se
• Topological Phase Transition and Texture Inversion in a Tunable Topological Insulator
• A sudden collapse in the transport lifetime across the topological phase transition in $(B{i}_{1-x}I{n}_x{)}_{2}S{e}_3$
• Unexpected mass acquisition of Dirac fermions at the quantum phase transition of a topological insulator
• Magneto-optics of massive Dirac fermions in bulk Bi2Se3
• On the nature of the band inversion and the topological phase transition in (Pb,Sn)Se
• Fine structure of "zero-mode" Landau levels in HgTe/HgCdTe quantum wells
• Temperature-induced topological phase transition in HgTe quantum wells
• Temperature-driven single-valley Dirac fermions in HgTe quantum wells
• Negative longitudinal magnetoresistance from anomalous N=0 Landau level in topological materials
• Magnetoresistance and valley degree of freedom in bulk bismuth
• Finite-size and composition-driven topological phase transition in (Bi${}_{1-x}$In${}_x$)${}_2$Se${}_3$ thin films
• Temperature-dependent magnetospectroscopy of HgTe quantum wells
• First-order quantum phase transition in three-dimensional topological band insulators
• Topological phase transition with nanoscale inhomogeneity in (Bi${}_{1-x}$In${}_x$)${}_2$Se${}_3$

Cited by in corpus (6)

• Dirac parameters and topological phase diagram of Pb1-xSnxSe from magneto-spectroscopy
• Landau level spectroscopy of Bi${}_2$Te${}_3$
• Landau level spectroscopy of PbSnSe topological crystalline insulator
• Revealing temperature evolution of the Dirac band in ZrTe${}_5$ via magneto-infrared spectroscopy
• Interaction between interface and massive states in multivalley topological heterostructures
• Spinor-dominated magnetoresistance driven by the topological phase transition in $\beta$-Ag${}_2$Se