g factor of topological interface states in Pb1-xSnxSe quantum wells

Topological crystalline insulators from the Pb1-xSnxSe family host textbook Dirac surface states that are nearly electron-hole symmetric and isotropic in momentum space. The high mobility of charge carriers possible in these materials allows one to reach the quantum limit at reasonably achievable magnetic fields. We exploit this advantage to combine magnetooptical Landau level spectroscopy, Shubnikov-de Haas transport measurement, and consistent modeling of the two experiments to precisely extract the band parameters of the topological states of this system along with their g factor. We find an enhanced g factor with field dependence compared with bulk states. This information is vital to the realization and understanding of novel quantized Hall effect, stemming from the mirror protected valley-degenerate Dirac states of this material family.