Charge Density Waves as a Tool to Achieve Idealized Topological Semimetals

Topological materials have been the source of many exciting new discoveries. The fast development of high throughput materials search programs has led to the identification of many topological materials in inorganic materials database. Despite the rapid progress, many topological materials that have been discovered suffer from non-ideal band structures, i.e. the topological bands are frequently convoluted with trivial ones, and band structure features of interest can appear far below the Fermi level. One strategy that has been utilized to achieve "better" topological materials has been chemical doping, which can shift the chemical potential to the points of interest. This strategy, however, does not help to remove interfering bands from the Fermi level. Here we introduce a new strategy to design nearly idealized topological semimetals, by taking advantage of a charge density wave (CDW) and non-symmorphic symmetry. We further show experimental verification of this strategy in single crystals of GdSb_xTe_2-x-δ by studying the electronic structure with angle-resolved photoemission spectroscopy (ARPES).