****Technical Abstract**** This CAREER grant supported by the Division Materials Research aims to have a crystal growth of new and perfect topological insulators/superconductors and exploration of Dirac surface state of the perfectly grown topological insulators (TIs). It also aims to integrate research in experimental condensed matter physics and development of a unique physics educational program at Missouri University of Science and Technology (S&T). New methods will be used to grow perfect bulk insulating TIs and to fabricate large surface-to-volume ratio of TI nanowire arrays. These perfect topological materials are necessary for Dirac surface current detection which is important for both new physics exploration such as studies of Majorana fermion and axion electrodynamics, and technological applications such as spintronic and quantum computing devices. Shubnikov-de Haas oscillations, Aharonov-Bohm effect and Altshuler-Aronov-Spivak interference on the perfectly grown TIs will be performed to estimate surface Dirac electron effective mass and decay length. Surface resistivity measurements under magnetic fields up to 45 T will then be carried out for the investigation of fractional quantum Hall effect which is a big quest in the field concerning the role of interactions and strong correlations in topological states of matter.
Topological insulator (TI) is a new quantum material which has insulating property in its bulk but has high conductivity of electrons on its surface. This surface conducting state is predicted to be a solution for future computing technology. However, surface transport measurements are challenging due to the imperfections of the current existing TIs. A new synthesis technique that utilizes a reduced confining reaction space will be applied to grow perfect bulk insulating crystals in order to permit surface current detection. This electronic transport detection of the surface electrons or the surface Dirac state is necessary for heat dissipation-less spintronic devices where electron spin manipulation can be performed by interfacing a perfect TI and a superconductor for potential fault-tolerant quantum computing applications. Besides, TIs can act as a bridge to bring together high energy and condensed matter physicists to search for long-sought particle such as the Majorana fermion i.e. a fermion which is its own anti-particle and an intermediate particle for electric and magnetic field interactions called the axion which could provide a clue to the mystery of dark matter in cosmology. This CAREER grant also helps to integrate the material synthesis in solid state physics course taught in S&T and to present physics shows targeted to local K-12 students.