arXiv subjects

Suvendu Ghosh

Publications and source records attributed to Suvendu Ghosh.

3 recordsLinked to original sources

arXiv2024

Topological Optical Pseudospin Injection Beyond Weyl Semimetals

Photoinduced effects are now reckoned to be important tools to reveal a rich gamut of entrancing physics in topological materials, which are normally inaccessible to conventional probes. Here we investigate one of these intriguing effects, namely, optical pseudospin injection (OPI) beyond ordinary Weyl semimetals (WSMs), specifically in multi-WSMs (mWSMs) and higher-order WSMs. Remarkably, we demonstrate that OPI in mWSMs is independent of the frequency of the light and linearly proportional to the quantized topological charge as a consequence of the inherent band linearity in their dispersions. Interestingly, while the response does not depend on the tilting of a type-I node, it is a decreasing function of the same in type-II mWSMs. We also reveal that the frequency independence can be destroyed either by going beyond a certain cutoff frequency under lattice regularization or by going to a higher-order Weyl phase. The predicted signatures of OPI beyond the ordinary WSM could be experimentally exploited, leading to effective access as well as distinguishing between different nontrivial Weyl topologies.

cond-mat.mes-hall↗

arXiv2024

Signature of nodal topology in nonlinear quantum transport across junctions in Weyl and multi-Weyl semimetals

We investigate quantum transport through a rectangular potential barrier in Weyl semimetals (WSMs) and multi-Weyl semimetals (MSMs), within the framework of Landauer-Büttiker formalism. Our study uncovers the role of nodal topology imprinted in the electric current and the shot noise. We find that, in contrast to the finite odd-order conductance and noise power, the even-order contributions vanish at the nodes. Additionally, depending on the topological charge ($J$), the linear conductance ($G_1$) scales with the Fermi energy ($E_F$) as $G_1^{E_F>U}\propto E_F^{2/J}$. We demonstrate that the $E_F$-dependence of the second-order conductance and shot noise power could quite remarkably distinguish an MSM from a WSM depending on the band topology, and may induce several smoking gun experiments in nanostructures made out of WSMs and MSMs. Analyzing shot noise and Fano factor, we show that the transport across the rectangular barrier follows the sub-Poissonian statistics. Interestingly, we obtain universal values of Fano factor at the nodes unique to their topological charges. The universality for a fixed $J$, however, indicates that only a fixed number of open channels participate in the transport through evanescent waves at the nodes. The proposed results can serve as a potential diagnostic tool to identify different topological systems in experiments.

cond-mat.mes-hall↗

arXiv2020

Chirality-dependent planar Hall effect in inhomogeneous Weyl semimetals

The planar Hall effect (PHE), the appearance of an in-plane transverse voltage in the presence of co-planar electric ($\mathbf{E}$) and magnetic ($\mathbf{B}$) fields, occurs in regular Weyl semimetals (WSMs) as one of the fundamental manifestations of chiral anomaly. A major issue, therefore, is whether there are alternate route to PHE, without invoking chiral anomaly. We demonstrate that PHE exists in an inhomogeneous Weyl semimetal (IWSM) even in the absence of the aforesaid anomaly. Using semiclassical Boltzmann transport theory, we show that PHE appears in an IWSM due to the strain-induced chiral gauge potential, which couples to the Weyl fermions of opposite chirality with opposite sign. Our study shows a resultant phase shift in the current associated with opposite chirality Weyl nodes, which, remarkably, leads to a finite chirality-dependent planar Hall effect (CPHE) in the IWSMs. Interestingly, we show that a small tilt in the Weyl node can generate a pure CPHE even in the absence of an applied magnetic field. The CPHE has important implications in `chiralitytronics'. We also discuss the experimental feasibility of these novel effects of strain in type-I IWSMs.

cond-mat.str-el↗