Gate-tunable Tellurene Demonstrates 70% Negative Magnetoresistance at Zero Magnetic Field

The search for materials exhibiting exceptionally large changes in electrical resistance under magnetic fields continues to drive innovation in electronics, and recent work by Marcello B. Silva Neto (Universidade Federal do Rio de Janeiro), Chang Niu (Purdue University), and Marcus V. O. Moutinho (Universidade Federal do Rio de Janeiro), along with colleagues Pierpaolo Fontana, Claudio Iacovelli, and Victor Velasco, reveals a giant negative magnetoresistance in tellurene, a two-dimensional material. The team demonstrates a remarkable reduction in electrical resistance, reaching a substantial percentage of the zero-field value, when a magnetic field is applied, a phenomenon that persists across a wide range of field strengths at very low temperatures. This record-breaking effect, they find, arises from the unique quantum geometry of tellurene and is linked to novel mechanisms involving enhanced diffusion and a spin interaction that effectively locks the motion of electrons, establishing a new understanding of how geometry can control electronic transport in advanced materials.

Tellurium Exhibits Negative Magnetoresistance Properties

Researchers are unraveling the unusual electrical behavior of two-dimensional tellurium, a material that exhibits a decrease in electrical resistance when exposed to a magnetic field, a phenomenon known as negative magnetoresistance. This research focuses on understanding the origins of this effect and characterizing its behavior at a fundamental level. The team discovered that the curvature of the material’s electronic band structure plays a crucial role in this negative magnetoresistance. The results demonstrate that the magnitude of this negative magnetoresistance depends on the orientation of the magnetic field and is sensitive to the concentration of charge carriers within the material, as well as temperature.,.

Tellurene Synthesis and Giant Negative Magnetoresistance Measurement

Scientists have pioneered a new approach to controlling electronic transport in tellurene, achieving a substantial 70% reduction in electrical resistance without any applied magnetic field. This giant negative magnetoresistance persists even in extremely strong magnetic fields, up to 42 Tesla, at very low temperatures. The tellurene films were created using a hydrothermal growth method and transferred onto silicon dioxide substrates. High-quality Hall bar devices were fabricated using electron beam lithography and atomic layer deposition, enabling precise control over the material’s electronic properties. Theoretical calculations, employing density-functional theory, revealed a unique spin texture and a non-trivial quantum metric within the tellurene structure, crucial to understanding the observed enhancement of diffusion and the resulting giant negative magnetoresistance.,.

Giant Negative Magnetoresistance in Tellurene Films

This work reports the discovery of a significant negative magnetoresistance in tellurene films, demonstrating a remarkable 60% reduction in resistance at zero magnetic field. Experiments reveal that this effect remains strong over a wide range of magnetic fields, up to 35 Tesla, at cryogenic temperatures. The negative magnetoresistance is most pronounced when the material’s electronic properties are tuned to a specific point near a Weyl node in the conduction band, suggesting a geometric origin for the phenomenon. Researchers observed distinct magnetoresistive behaviors depending on the type of charge carrier, with n-type tellurene exhibiting negative magnetoresistance and p-type tellurene showing positive magnetoresistance. Analysis of the carrier density dependence of the longitudinal magnetoresistance revealed well-defined quantum Hall plateaus, confirming the material’s high electronic quality.,.

Tellurene’s Giant Negative Magnetoresistance Explained

This research demonstrates a significant new phenomenon, a giant negative magnetoresistance, in tellurene films, achieving a remarkable change in resistance without any applied magnetic field. The team established that this effect originates from the material’s unique geometric properties, specifically linked to the presence of Weyl nodes in the conduction band, rather than conventional or semiclassical dynamics. They propose two mechanisms driving this behavior: a geometric enhancement of diffusion, facilitated by the material’s structure, and a novel quantum-geometric-induced Drift-Zeeman interaction that influences electron spin. The findings reveal a previously unexplored quantum mechanical effect, the memory of a wavefunction’s geometric structure, which dictates the macroscopic transport properties of the material.

Experimental data strongly align with the theoretical model, confirming the role of the quantum metric in influencing electron behavior. The researchers suggest potential applications, including non-saturating magnetoresistive sensors and energy-efficient magnetic random-access memory (MRAM) devices with field-programmable resistance. They acknowledge that the observed behavior transitions from two-dimensional to three-dimensional characteristics at higher temperatures, a factor that may require consideration in future device development.