Strong spin-orbit anisotropy in PbTe nanowire quantum dots with negligible charging energy

PbTe is a IV-VI narrow-bandgap semiconductor with many unique characteristics of interest for quantum technology research. Notably among these is its large static dielectric constant—exceeding 1000 at cryogenic temperatures—which suppresses Coulomb blockade in quantum dots and thus allows for the direct spectroscopy of spin-orbital states. Here we present our progress in characterizing the spin-orbit interaction in PbTe quantum dots defined in nanowires. We demonstrate that our samples have significant spin-orbit coupling strengths and large effective Landé g-factors. We also show that these properties are highly anisotropic and typically extremized synchronously with each other. We analyze this anisotropy in detail and discuss its implications for the potential development of PbTe spin qubits.