| Charge density wave formation is explored in the rare-earth tritelluride family of compounds (RTe3, R = Y, La-Nd, Sm, Gd-Tm). These quasi-two-dimensional compounds host a simple lattice modulation with very little variance across the series. They have an especially simple electronic structure, which can be easily tuned by chemical pressure via rare-earth substitution.; The Fermi surface (FS) of RTe3 is derived mainly from the p-orbitals of the Te atoms, which are arranged in double layers of nearly square-planar sheets. Despite the nearly four-fold symmetry of the Fermi surface and electronic structure, it is energetically favorable for RTe3 to form an incommensurate CDW that is unidirectional, rather than bidirectional---that is, of "stripe" rather than "checkerboard" symmetry. This CDW wavevector lies along one of the in-plane directions and partially nests nearly-parallel regions of the FS.; In this thesis, I present the results of resistivity and high resolution x-ray diffraction measurements that follow the CDW transition temperatures across the RTe3 series. Critical temperatures Tc1 were found to vary remarkably across the series, attributed to the subtle effects of chemical pressure on the electronic structure. For the compounds with the smallest lattice parameters (R = Dy, Ho, Er, Tm), second CDW transitions were observed at lower temperatures Tc2. X-ray diffraction measurements for ErTe3 revealed this to be the onset of a CDW with wavevector lying in the in-plane direction perpendicular to the first, which is reminiscent of bidirectional order. Yet, as this second CDW forms at a lower temperature than the first, and nests a Fermi surface that has been previous nested, this CDW state with two order parameters for perpendicular wavevectors may be more appropriately termed a "rectangular" state.; Quantum oscillation studies are also presented that probe the reconstructed FS of LaTe3. Additionally, antiferromagnetism arising from the local moments on the rare earth ions is explored, which has Neel temperatures generally much lower than the CDW transition temperatures.; The measurements presented in this thesis establish RTe 3 as a model CDW system and a potential "toy box" for future study. |
