Three-dimensional topological insulators are a new class of quantum matter which has interesting connections to nearly all main branches of condensed matter physics. In this article, we briefly review the advances in the field effect control of chemical potential in three-dimensional topological insulators. It is essential to the observation of many exotic quantum phenomena predicted to emerge from the topological insulators and their hybrid structures with other materials. We also describe various methods for probing the surface state transport. Some challenges in experimental study of electron transport in topological insulators will also be briefly discussed.
The Institute of Physics, Chinese Academy of Sciences, is in charge of the construction of the Synergetic Extreme Condition User Facility （SECUF） in Huairou, Beijing. The SECUF is a comprehensive facility focused on providing extreme physical conditions for scientific research, including an ultralow temperature, ultrahigh pressure, ultrahigh magnetic field, and ultrafast laser. The ultralow temperature will be realized by the sub-millikelvin （sub-mK） station, whose main component is an adiabatic nuclear demagnetization refrigerator （ANDR）. The refrigerator is designed to have a base temperature below 1 mK and a magnetic field up to 16 T for experiments, as well as a characteristic parameter of B/T ≥-104 T/K. In this review, we introduce adiabatic nuclear demagnetization refrigeration, thermometry from 10 mK to sub-mK, the properties and parameters of the ANDR of the SECUF, and related prospective research topics.
