Operation of graphene magnetic field sensors near the charge neutrality point

Abstract

Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomic-scale thickness, ultra-high carrier mobilities and low cost compared to conventional semiconductor sensors. Because of its Dirac band structure, graphene sensors differ from semiconductor sensors in that both electrons and holes participate in the carrier transport. This two-channel transport complicates the sensor operation and causes performance tradeoffs that demand careful examination. Here, we examine the operation of graphene sensors operated near the charge neutrality point (CNP) where two-channel transport prevails. We find that, while the largest magnetoresistance occurs exactly at the CNP, the maximum realizable Hall sensitivities occur away from the CNP and depend on linearity constraints and power limitations. In particular, a more stringent linearity constraint reduces the realizable sensitivities for mobilities above a critical value µ c , which scales with magnetic field.

Magnetic field detection limits for ultraclean graphene Hall sensors

“…2c, upper panel). At gate voltages near the charge neutrality point (CNP), the coexistence of electrons and holes makes the Hall voltage nonlinear in magnetic field 31 . Elsewhere, the Hall voltage is linear in B at least up to 100 mT, and R H~n −1 V g −1 assuming a simple capacitive coupling of the gate to the mobile carrier density 19 .…”

Strong magnetoresistance in a graphene Corbino disk at low magnetic fields

“…For classical magnetoresistance, both linear and quadratic behavior is expected according to effective medium theory [10,11]. Owing to strong demand for magnetic field sensors based on magnetotransport, various ways to generate large magnetoresistance in graphene have been developed in monolayer [9,[12][13][14][15][16][17][18][19][20][21] and multilayer graphene [22,23]. In this work, we demonstrate that intrinsic behavior of suspended graphene in the Corbino-ring geometry, which already as such yields a strong magnetoresistance.…”

The tunable electric and magnetic properties of 2D MXenes and their potential applications

“…Nevertheless, tunable magnetic properties in 2D materials are highly demanding due to applicability in quantum computation, nanomedicine, logic and memory operations, spintronics, magnetic sensors, etc. [94][95][96][97][98] . Thus, the magnetic anisotropy property of magnetic 2D materials can be realized to explore the practically important 2D materials.…”