Observation of a Smoothly Tunable Dirac Point in Ge(Bi_xSb_1-x)₂Te₄

Next-generation topological devices use topologically protected surface states to drive electronic transport. In this study, we examine Ge(Bi_xSb_1-x)₂Te₄, a tunable topological system, for a range of x values from 0 to 1 using a combination of Fourier-Transform Scanning Tunneling Spectroscopy (FT-STS) and Angle-Resolved Photoemission Spectroscopy (ARPES). We show that the Dirac point changes linearly with x, crossing the Fermi energy at x = 0.7. This novel observation of a smoothly tunable, isolated Dirac point traversing the topological transport regime and having strong linear dependence with substitution can be critical in designing new topological spintronics applications.