Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userConductance oscillation in surface junctions of Weyl semimetals
78
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Fermi arc surface states, the manifestation of the bulk-edge correspondence in Weyl semimetals, have attracted much research interest. In contrast to the conventional Fermi loop, the disconnected Fermi arcs provide an exotic 2D system for exploration of novel physical effects on the surface of Weyl semimetals. Here, we propose that visible conductance oscillation can be achieved in the planar junctions fabricated on the surface of Weyl semimetal with a pair of Fermi arcs. It is shown that Fabry-P{e}rot-type interference inside the 2D junction can generate conductance oscillation with its visibility strongly relying on the shape of the Fermi arcs and their orientation relative to the strip electrodes, the latter clearly revealing the anisotropy of the Fermi arcs. Moreover, we show that the visibility of the oscillating pattern can be significantly enhanced by a magnetic field perpendicular to the surface taking advantage of the bulk-surface connected Weyl orbits. Our work offers an effective way for the identification of Fermi arc surface states through transport measurement and predicts the surface of Weyl semimetal as a novel platform for the implementation of 2D conductance oscillation.
rate research
Read More
Magnetotransport provides key experimental signatures in Weyl semimetals. The longitudinal magnetoresistance is linked to the chiral anomaly and the transversal magnetoresistance to the dominant charge relaxation mechanism. Axial magnetic fields that act with opposite sign on opposite chiralities facilitate new transport experiments that probe the low-energy Weyl nodes. As recently realized, these axial fields can be achieved by straining samples or adding inhomogeneities to them. Here, we identify a robust signature of axial magnetic fields: an anomalous scaling of the conductance in the diffusive ultraquantum regime. In particular, we demonstrate that the longitudinal conductivity in the ultraquantum regime of a disordered Weyl semimetal subjected to an axial magnetic field increases with both the field strength and sample width due to a spatial separation of charge carriers. We contrast axial magnetic with real magnetic fields to clearly distinguish the different behavior of the conductance. Our results rely on numerical tight-binding simulations and are supported by analytical arguments. We argue that the spatial separation of charge carriers can be used for directed currents in microstructured electronic devices.
Smooth interfaces of topological systems are known to host massive surface states along with the topologically protected chiral one. We show that in Weyl semimetals these massive states, along with the chiral Fermi arc, strongly alter the form of the Fermi-arc plasmon, Most saliently, they yield further collective plasmonic modes that are absent in a conventional interfaces. The plasmon modes are completely anisotropic as a consequence of the underlying anisotropy in the surface model and expected to have a clear-cut experimental signature, e.g. in electron-energy loss spectroscopy.
We predict a linear logarithmical scaling law of Bloch oscillation dynamics in Weyl semimetals (WSMs), which can be applied to detect Weyl nodal points. Applying the semiclassical dynamics for quasiparticles which are accelerated bypassing a Weyl point, we show that transverse drift exhibits asymptotically a linear log-log relation with respect to the minimal momentum measured from the Weyl point. This linear scaling behavior is a consequence of the monopole structure nearby the Weyl points, thus providing a direct measurement of the topological nodal points, with the chirality and anisotropy being precisely determined. We apply the present results to two lattice models for WSMs which can be realized with cold atoms in experiment, and propose realistic schemes for the experimental detection. With the analytic and numerical results we show the feasibility of identifying topological Weyl nodal points based on the present prediction.
Surface plasmon polaritons in a strained slab of a Weyl semimetal with broken time-reversal symmetry are investigated. It is found that the strain-induced axial gauge field reduces frequencies of these collective modes for intermediate values of the wave vector. Depending on the relative orientation of the separation of Weyl nodes in momentum space, the surface normal, and the direction of propagation, the dispersion relation of surface plasmon polaritons could be nonreciprocal even in a thin slab. In addition, strain-induced axial gauge fields can significantly affect the localization properties of the collective modes. These effects allow for an in situ control of the propagation of surface plasmon polaritons in Weyl semimetals and might be useful for creating nonreciprocal devices.
We theoretically investigate surface plasmon polaritons propagating in the thin-film Weyl semimetals. We show how the properties of surface plasmon polaritons are affected by hybridization between plasmons localized at the two metal-dielectric interfaces. Generally, this hybridization results in new mixed plasmon modes, which are called short-range surface plasmons and long-range surface plasmons, respectively. We calculate dispersion curves of these mixed modes for three principle configurations of the axion vector describing axial anomaly in Weyl semimetals. We show that the partial lack of the dispersion and the non-reciprocity can be controlled by fine-tuning of the thickness of the Weyl semimetals, the dielectric constants of the outer insulators, and the direction of the axion vector.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
