Topology andPTsymmetry in a non-Hermitian Su-Schrieffer-Heeger chain with periodic hopping modulation.

We study the effect of periodic hopping modulation in a Su-Schrieffer-Heeger (SSH) chain with an additional onsite staggered imaginary potential (of strength). Such dissipative, non-Hermitian (NH) extension amply modifies the features of the topological trivial phase (TTP) and the topological nontrivial phase (TNP) of the SSH chain, more so with the periodic hopping distribution. Generally a weak NH potential can respect the parity-time (PT) symmetry keeping the energy eigenvalues real, while a strong potential breaksPTconservation leading to imaginary edge state and complex bulk state energies in the system.

Floquet analysis on an irradiated nodal surface semimetal with non-symmorphic symmetry.

A nodal surface semimetal (NSSM) features symmetry enforced band crossings along a surface within the three-dimensional (3D) Brillouin zone (BZ) and a presence of a nonsymmorphic symmetry there pushes such surfaces to stick to the BZ center or boundaries. The topological robustness of the same does not always come with nonzero Berry fluxes. We consider two such NS, one with zero and another with nonzero topological charges and investigate the effect of light irradiation on them.

Edge state behavior in a Su-Schrieffer-Heeger like model with periodically modulated hopping.

Su-Schrieffer-Heeger (SSH) model is one of the simplest models to show topological end/edge states and the existence of Majorana fermions. Here we consider a SSH like model both in one and two dimensions where a nearest neighbor hopping features spatially periodic modulations. In the 1D chain, we witness appearance of new in-gap end states apart from a pair of Majorana zero modes (MZMs) when the hopping periodicity go beyond two lattice spacings.

Chiral anomaly induced magnetoconductances in an irradiated type-I Weyl semimetal.

Magneto conductivities in Weyl semimetals (WSMs) in presence of small fields are studied using quasi-classical Boltzmann transport equations. Following such formalism here we consider irradiation via circularly polarized light on a two-node time reversal breaking WSM already under a dc/static electric field and study the magneto-transport properties due to the presence of chiral anomaly. Chiral anomaly affects both longitudinal magnetoconductivity as well as planar Hall conductivity.

Fermi level fluctuations, reduced effective masses and Zeeman effect during quantum oscillations in nodal line semimetals.

We probe quantum oscillations in nodal line semimetals (NLSM) by considering an NLSM continuum model under strong magnetic field and report the characteristics of the Landau level (LL) spectra and the fluctuations in the Fermi level as the field in a direction perpendicular to the nodal plane is varied through. Based on the results on parallel magnetization, we demonstrate the growth of quantum oscillation with field strength as well as its constancy in period when plotted against 1/. We find that the density of states (DOS) which show series of peaks in succession, witness bifurcation of those peaks due to Zeeman effect.

Quantum oscillation and Landau-Zener transition in untilted nodal line semimetals under a time-periodic magnetic field.

Nodal line semimetals (NLSM) exhibit interesting quantum oscillation (QO) characteristics when acted upon by a strong magnetic field. We study the combined effect of strong direct and alternating magnetic field, perpendicular to the nodal plane in an untilted NLSM in order to probe the behavior of the low lying Landau level states that can periodically become gapless for suitably chosen field parameters. The oscillatory field variation, as opposed to a steady one, has interesting impact on the QO phenomena with the Landau tubes crossing the Fermi surface extremally two times per cycle.