Uniformity of the pseudomagnetic field in strained graphene

Abstract

We present a study on the uniformity of the pseudomagnetic field in graphene as a function of the relative orientation between the graphene lattice and straining directions. For this, we strained a regular micron-sized graphene hexagon by deforming it symmetrically by displacing three of its edges. By simulations, we found that the pseudomagnetic field is strongest if the strain is applied perpendicular to the armchair direction of graphene. For a hexagon with a side length of 1 µm, the pseudomagnetic field has a maximum of 1.2 T for an applied strain of 3.5% and it is uniform (variance < 1%) within a circle with a diameter of ∼ 520 nm. This diameter is on the order of the typical diameter of the laser spot in a state-of-the-art confocal Raman spectroscopy setup, which suggests that observing the pseudomagnetic field in measurements of shifted magneto-phonon resonance is feasible.

Raman scattering of graphene‐based systems in high magnetic fields

“…It has been realized recently that strain fields in graphene are equivalent to pseudo‐magnetic fields and can profoundly modify the electronic excitation spectrum by inducing Landau quantization without externally applied magnetic field. MPR can be used as a probe of strain in a well‐defined regime where MPR is active, and combined with the micrometer scale spatial resolution achievable with visible optics, MPR can bring a precise spatial picture of strain distribution as was recently proposed in Low et al and Verbiest et al Interesting and still unexplored yet is the regime of very high magnetic fields, for which the cyclotron resonance mode, the intraband excitation in a doped graphene sample, is tuned to the G band energy. Mainly because it occurs at magnetic fields above B = 100 T, this coupling is expected to give the most pronounced anti‐crossing and mode‐mixing, but such high fields are today only achieved with pulsed magnetic field installation and are not compatible with typical integration times of Raman scattering experiments.…”

Tunable anomalous Andreev reflection and triplet pairings in spin-orbit-coupled graphene

“…Furthermore, graphene has the capability of sustaining strain and deformations without rupture 36,37 . The application of strain to graphene layers can result in important and interesting phenomena [38][39][40][41][42][43][44][45][46][47] . For example, the interplay of massive electrons with spin orbit coupling in the presence of strain in a graphene layer yields controllable spatially separated spin-valley filtering 38,39 .…”

Magnetic phases in periodically rippled graphene

“…Non-uniform strain occurs in the intrinsic ripples that appear in free standing graphene [7][8][9][10] and also when the graphene sheet is bonded to a substrate [11][12][13][14][15][16]. Effective magnetic fields constant on large areas can be obtained by strain engineering [17][18][19][20][21][22]. The effective fields generated by non uniform strain can interfere with externally applied magnetic fields giving rise to new physical effects [23][24][25].…”