Related papers: Gigantic magnetochiral anisotropy in the topologic…
Magnetic topological materials represent a class of compounds whose properties are strongly influenced by the topology of the electronic wavefunctions coupled with the magnetic spin configuration. Such materials can support chiral…
Topological phases of matter have established a new paradigm in physics, bringing quantum phenomena to the macroscopic scale and hosting exotic emergent quasiparticles. In this thesis, I theoretically and experimentally demonstrate with my…
A newly discovered topological insulator (AgxPb1-xSe)5(Bi2Se3)3m, m=2, has a band gap of 0.5 eV, the largest value ever reported in topological insulators (TIs). We present a magnetoconductivity study of the Dirac electrons of this compound…
Recent experiments in ferromagnetic atomic-sized contacts have shown that the anisotropic magnetoresistance (AMR) is greatly enhanced and has an asymmetric angular dependence as compared with that of bulk samples. The origin of these…
The topological Hall effect, driven by the exchange interaction between conduction electrons and topological magnetic textures such as skyrmions, is a powerful probe for investigating the topological properties of magnetic materials.…
We study an intrinsic relation between the topology of bulk electronic states and magnetic responses of Majorana Kramers pairs, Kramers pairs of Majorana fermions, on a surface of time-reversal-invariant topological superconductors.…
ZrTe$_5$ and HfTe$_5$ have attracted increasingly attention recently since the theoretical prediction of being topological insulators (TIs). However, subsequent works show many contradictions about their topological nature.Three possible…
Topological Dirac semimetals with accidental band touching between conduction and valence bands protected by time reversal and inversion symmetry are at the frontier of modern condensed matter research. Theoretically one can get Weyl and/or…
Magnetoresistance typically exhibits even symmetry with respect to the magnetic field, owing to time reversal symmetry (TRS) as dictated by Onsager reciprocity relations. However, in certain systems where TRS is broken, magnetoresistance…
Recent observations of topological spin textures brought spintronics one step closer to new magnetic memories. Nevertheless, the existence of Skyrmions, as well as their stabilization, require very specific intrinsic magnetic properties…
The relation between bulk topological invariants and experimentally observable physical quantities is a fundamental property of topological insulators and superconductors. In the case of chiral symmetric systems in odd spatial dimensions…
The Dirac material ZrTe$_5$ at very low carrier density was recently found to be a nodal-line semimetal, where ultra-flat bands are expected to emerge in magnetic fields parallel to the nodal-line plane. Here we report that in very low…
We report the experimental realization of Dirac semimetal state in NdSb, a material with antiferromagnetic ground state. The occurrence of topological semimetal state has been well supported by our band structure calculations and the…
A phase transition between topologically distinct insulating phases involves closing and reopening of the bandgap. Close to this topological phase transition, the bulk energy spectrum is characterized by a massive Dirac dispersion, where…
Transition-metal dichalcogenides (WTe$_2$ and MoTe$_2$) have drawn much attention, recently, because of the nonsaturating extremely large magnetoresistance (XMR) observed in these compounds in addition to the predictions of likely type-II…
Ferromagnetic resonance (FMR) study of magnetic anisotropy is presented for thin layers of IV-VI diluted magnetic semiconductor Ge1-xMn xTe with x=0.14 grown by molecular beam epitaxy (MBE) on KCl (001) substrate with a thin PbTe buffer.…
The layered ternary compound TaIrTe4 is an important candidate to host the recently predicted type-II Weyl Fermions. However, a direct and definitive proof of the absence of inversion symmetry in this material, a prerequisite for the…
On the surface of time-reversal-invariant topological superconductors, Kramers pairs of Majorana fermions with chiral and crystalline symmetries exhibit completely uniaxial or octupole anisotropic magnetic response. This paper reports…
Giant vortices with higher phase-winding than $2\pi$ are usually energetically unfavorable, but geometric symmetry constraints on a superconductor in a magnetic field are known to stabilize such objects. Here, we show via microscopic…
The diverse electronic properties of transition metal chalcogenides can be very sensitive to crystal imperfections. A new crystal growth technique, known as horizontal flux transport, offers a route to improved crystal quality. By refining…