The nonlinear Hall effect (NLHE) emerges as a significant phenomenon within the realm of condensed matter physics, offering new avenues and theoretical frameworks for harnessing electrical energy. A groundbreaking study conducted by a prominent research team has uncovered remarkable NLHE and wireless rectification capabilities in elemental tellurium (Te) at room temperature. Reported in the prestigious journal Nature Communications, this work signifies a pivotal shift in how we understand nonlinear responses in semiconductors, particularly in their practical utility for energy harvesting and electronic applications.
Historically, the study of NLHE faced numerous challenges, notably in generating adequate Hall voltage outputs and requiring extremely low operational temperatures. Earlier investigations had demonstrated NLHE effects in materials like Dirac semimetal BaMnSb2 and Weyl semimetal TaIrTe4, yet these systems offered limited voltage output and tuning options, thus hampering their practical implementation in real-world applications. The complexity of achieving observable NLHE at room temperature further contributed to the stagnation of advancements in this field.
Motivated by these previous shortcomings, researchers turned their focus to semiconductor materials, particularly tellurium due to its intriguing atomic structure comprised of one-dimensional helical chains. This unique arrangement of tellurium atoms naturally breaks inversion symmetry, presenting a promising candidate for exhibiting enhanced NLHE. Upon experimenting with Te thin flakes, the team observed unprecedented NLHE at room temperature, achieving a remarkable second-harmonic output of up to 2.8 mV – a value significantly higher than previously reported results.
A detailed analysis revealed that the dominant factors contributing to the observed NLHE in tellurium were predominantly extrinsic scattering phenomena, combined with the surface symmetry breakdown inherent to the thin flake structure. This insight not only elucidates the underlying physics governing the effect but also demonstrates how material engineering can be leveraged to fine-tune electrical outputs. Such a breakthrough in understanding lays the groundwork for new designs in electronic devices across various applications.
Building upon these findings, the research team ventured to explore the capabilities of tellurium in wireless RF rectification. By replacing the conventional alternating current with radiofrequency signals, they successfully achieved consistent rectified voltage outputs across an impressive frequency range of 0.3 to 4.5 GHz. Unlike traditional rectification technologies that depend on p-n junctions or metal-semiconductor interfaces, the hall rectification offered by tellurium’s intrinsic properties operates efficiently under zero bias, making it a formidable candidate for power harvesting and wireless charging technologies.
The implications of this research extend beyond mere academic interest; they pave the way for the development of advanced electronic devices capitalizing on nonlinear transport phenomena. By enhancing our comprehension of NLHE in semiconductor materials like tellurium, the work spearheaded by Prof. Zeng Changgan and Associate Researcher Li Lin from the University of Science and Technology of China opens new frontiers in energy harvesting strategies and next-generation wireless technologies. As we continue to unveil the intricacies of these fundamental effects, the journey towards more efficient and sustainable electronic systems is poised to thrive.