A. Al Luhaibi | Searcharxiv

arXiv2026

Analytical Treatment of Noise-Suppressed Klein Tunneling in Graphene with Possible Implications for Quantum-Dot Qubits

We study quantum tunneling through a potential barrier whose height fluctuates in time and is modeled by Gaussian white noise. We map the stochastic dynamics onto an equivalent time-independent Lindblad equation for the density matrix, allowing fully analytical solutions. For Schrödinger particles, noise introduces dissipation that suppresses Fabry-Pérot oscillations and yields an exponentially decaying transmission. Applying the same formalism to graphene, we demonstrate that noise induces a complex longitudinal wavevector within the barrier, leading to a strong suppression of transmission and Klein tunneling, even at normal incidence. Our approach promises improved control over Klein tunneling. These results demonstrate that noisy barriers can act as tunable dissipative elements, offering a pathway to enhanced control of electron transport in graphene-based devices. We also briefly discuss how our results could guide the design of graphene quantum dots for potential use in spin qubit devices.

cond-mat.mes-hall↗

arXiv2026

Fingerprints of an Imbert-Fedorov-like effect in the tunneling transmission of Rarita-Schwinger semi-metals

We study tunneling through a square barrier in a rotationally symmetric Rarita-Schwinger semi-metal and identify fingerprints of an Imbert-Fedorov-like effect in the tunneling transmission. The problem is intrinsically multichannel at all energies because there exist two propagating sectors with spin projections $m=1/2$ and $m=3/2$. We derive the transmission amplitudes analytically and compare the single-channel and coherent mixed-incidence cases in the two channels. Interestingly, we observe that tunneling at high energy shows a bias towards scattering into spin projection $3/2$ contributions. For single-channel injection, we find that the transmission remains symmetric under a mirror transformation of the incident angle. In contrast, for the coherent superposition, we find a directional asymmetry in the transmission probability $T(k_y)\neq T(-k_y)$. Importantly, this effect does not originate from an anisotropy of the dispersion. Instead, it arises from the phase structure of the multicomponent scattering states. The two spin projection sectors exhibit different scattering and barrier-propagation phases, which enter as interference terms when both channels appear as a coherent superposition. This interference term is identified as the cause of the broken mirror symmetry. We therefore discover an analog of the Imbert-Fedorov effect, at the level of interface-induced phase differences between internal wave components. Our result demonstrates that asymmetric tunneling can already occur in transport experiments, even in an idealized, isotropic multiband system, and should therefore not be automatically attributed solely to explicit band anisotropy.

cond-mat.mes-hall↗