Irradiation-Enabled Fermi-Level Control in Quantum Materials*

Fine-tuning the Fermi level is critical in optimizing device performance for microelectronics, enhancing superconducting critical temperatures, and improving power generation in energy harvesting applications. This precision is equally vital in topological materials, where specific electronic states and phenomena rely on the exact positioning of the Fermi level. Nevertheless, achieving precise control in three-dimensional bulk materials remains a significant challenge. The need for improved control over the Fermi level is further underscored by the growing demands of high-performance computing and advanced energy applications.

I will present a novel technique, "irradiation," for post-growth single crystals of the Weyl semimetal TaP. This innovative method offers superior control over doped material properties compared to conventional approaches, overcoming thermodynamic limitations and yielding promising results. Our theoretical calculations and experimental procedures on H⁻ ion irradiation on TaP successfully allow us to shift the Fermi level towards Weyl points. This rapid technique elevates the electron-hole compensation temperature in irradiated TaP by 150%. This work unveils new avenues for exploring and harnessing the distinct characteristics of quantum materials by affording precise Fermi-level manipulation in bulk crystals.