Stress-controlled n–p conductivity switch based on intercalated ZrTe₂

The ability to manipulate the electronic transport properties and electronic states in transition metal chalcogenides greatly expands the range of their application. Here, we investigate the effect of applied stress on the electrical conductivity of quasi-two-dimensional ZrTe₂ and several intercalated Ag_xZrTe₂ and Cu_xZrTe₂ crystals using pressure-dependent measurements of their Seebeck coefficients (thermoelectric powers) at room temperature. The pristine ZrTe₂ crystal is characterized by p-type semimetal conductivity, and the pressure dependence of its thermopower exhibits a broad wave-like maximum at about 2 GPa. Potentially, this feature is related to a charge density wave transition. The electrical conductivity in all the intercalated crystals is of n-type, but an applied pressure of about 1.5–3 GPa, dependent on crystal composition, reversibly inverts it to p-type. At pressures above 6 GPa, thermopower curves for all samples demonstrate a nearly identical and degenerate pressure behavior, thereby suggesting metallization of the samples. We verify the reproducibility of the above features by multiple pressure cycling of the samples up to 9 GPa. We, therefore, experimentally show that slightly intercalated ZrTe₂ crystals with n-type conductivity can be utilized as stress-controlled n-/p-switches of the conductivity type. We give and discuss simple examples of how the above n–p conductivity inversions could be potentially implemented in various modules for next-generation nanoelectronic devices.