arXiv subjects

Otman Bouladiane

Publications and source records attributed to Otman Bouladiane.

3 recordsLinked to original sources

arXiv2026

Floquet engineering of spin-valley selective transport in jacutingaite

We study electron transport through a monolayer jacutingaite (Pt$_2$HgSe$_3$) tunnel junction in which only the barrier is irradiated by off-resonant circularly polarized light, while the leads remain undriven. In the high-frequency regime, the driven barrier reduces to an effective static Dirac Hamiltonian with a photon-dressed, valley-dependent mass term. A staggered sublattice potential $V_z$ and a substrate-induced exchange field $m_s$ provide additional tunable mass terms. Using scattering theory, we compute spin- and valley-resolved transmission and reflection, as well as the Landauer conductance. Photon dressing shifts the barrier {Dirac masses} with opposite signs in the ($\boldsymbol{K}, \boldsymbol{K}'$) valleys and induces a splitting of the propagation thresholds. The finite barrier then produces channel-dependent Fabry--Pérot-type interference through the phase $q_x^{ηs_z}L$. We find broad parameter windows with near-perfect valley filtering ($|P_v|\simeq 100\%$) and substantial spin polarization ($|P_s|\sim 70\%$). The dominant spin and valley polarizations can be switched by tuning the drive amplitude $A_0$, $V_z$, and~$m_s$.

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↗

arXiv2026

Gate-tunable spin-valley transport via carrier velocity in monolayer WSe$_2$

We theoretically investigate spin- and valley-resolved quantum transport in monolayer tungsten diselenide (WSe$_2$) described by an effective massive Dirac Hamiltonian. Particular attention is devoted to a finite barrier region characterized by simultaneously modulated Fermi velocity and scalar potential. The barrier velocity $v_2$ is related to the external velocity $v_1$ through a velocity ratio $ξ=v_2/v_1$, motivated by an optical analogy with the Snell-Descartes law. The exact refraction condition depends on the full spin- and valley-resolved dispersion, and the simple ratio $ξ=v_2/v_1$ is recovered only in the massless, symmetric limit. The interplay of intrinsic spin-orbit coupling in the conduction and valence bands, quantified by $λ_c$ and $λ_v$, with spin- and valley-dependent Zeeman fields, $M_s$ and $M_v$, gives rise to substantial changes in the quasiparticle dispersion, leading to pronounced modifications of the transport characteristics. By solving the Dirac equation and enforcing current-conserving matching conditions at the interfaces, we compute the spin- and valley-dependent transmission probability and conductance. Our results demonstrate that the barrier velocity, scalar potential, incidence angle, incident energy, and barrier width serve as effective control parameters for transport, giving rise to strong anisotropy and resonant tunneling features. Furthermore, we show that both the magnitude and orientation of spin- and valley-polarized currents can be continuously tuned via velocity and potential modulation. These findings establish combined velocity and potential engineering as a powerful theoretical framework for controlling spin-valley physics in two-dimensional transition-metal dichalcogenides.

cond-mat.mes-hall↗