Global strain-induced scalar potential in graphene devices

Abstract

By mechanically distorting a crystal lattice it is possible to engineer the electronic and optical properties of a material. In graphene, one of the major effects of such a distortion is an energy shift of the Dirac point, often described as a scalar potential. We demonstrate how such a scalar potential can be generated systematically over an entire electronic device and how the resulting changes in the graphene work function can be detected in transport experiments. Combined with Raman spectroscopy, we obtain a characteristic scalar potential consistent with recent theoretical estimates. This direct evidence for a scalar potential on a macroscopic scale due to deterministically generated strain in graphene paves the way for engineering the optical and electronic properties of graphene and similar materials by using external strain.

Recent Progress in Strain Engineering on Van der Waals 2D Materials: Tunable Electrical, Electrochemical, Magnetic, and Optical Properties

“…The pseudo‐magnetic field also caused a difference in the interlayer and intralayer coupling of the bilayer graphene, resulting in the planar Hall effect ( Figure a). In another example for monolayer graphene, [ 44 ] the uniaxial strain of 0.21% induced scalar potential of 0.008 V, causing a shift in the Dirac point. The monolayer graphene was strained using a wedge setup and flexible polyimide substrate (Figure 2b).…”

“…Strain engineering has also been demonstrated theoretically and experimentally to be able to change the superconducting transition temperature (T c ) or superconducting gap-closing temperature (T g ) of conventional and unconventional superconductors. [54][55][56][57][58][59][60][61][62][63][64][65][66] For instance, Tresca et al studied the effect of inplane strain on electronic, mechanical, and magnetic properties [44] Copyright 2021, The Authors, published by Springer Nature. c) Multilayer WSe 2 strained on bent PET showed d) shift in flat-band voltage.…”

“…a,b) Reproduced under the terms of the CC‐BY Creative Commons Attribution 4.0 International license ( https://creativecommons.org/licenses/by/4.0). [ 44 ] Copyright 2021, The Authors, published by Springer Nature. c) Multilayer WSe 2 strained on bent PET showed d) shift in flat‐band voltage.…”

“…Effects of strain on electrical transport of 2D materials reveal intriguing physics and future applications. [44][45][46][47][48][49][50][51] Besides several pioneering studies, [46,47] one recent example of such novel physics in strain systems is the work reported by Ho et al, [49] who demonstrated the introduction of the pseudo-magnetic field in bilayer graphene using a corrugated hBN surface to introduce strain. Low-temperature measurements of the quadratic dependence of second harmonic Hall voltage with current showed clear evidence of Berry curvature change from the strain-induced pseudo-magnetic field.…”

“…Figure 2. a) Strained graphene on polyimide substrate; b) shift in charge-neutral point due to shifting in Dirac point. a,b) Reproduced under the terms of the CC-BY Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0) [44]. Copyright 2021, The Authors, published by Springer Nature.…”