Related papers: Signatures of a topological Weyl loop in Co$_3$Sn$…

Very recently, the half-metallic compound Co$_3$Sn$_2$S$_2$ was predicted to be a magnetic WSM with Weyl points only 60 meV above the Fermi level ($E_F$). Owing to the low charge carrier density and large Berry curvature…

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…

Weyl semimetals have sparked intense research interest, but experimental work has been limited to the TaAs family of compounds. Recently, a number of theoretical works have predicted that compounds in the Mo$_x$W$_{1-x}$Te$_2$ series are…

Weyl semimetal (WSM), a novel state of quantum matter, hosts Weyl fermions as emergent quasiparticles resulting from the breaking of either inversion or time-reversal symmetry. Magnetic WSMs that arise from broken time-reversal symmetry…

Topological band theory has revolutionized our understanding of electronic structure of materials, in particular, a novel state - Weyl semimetal - has been predicted for systems with strong spin-orbit coupling (SOC). Here, a new class of…

Co$_3$Sn$_2$S$_2$ is a magnetic Weyl semimetal, in which ferromagnetic ordering at 177K is predicted to stabilize Weyl points. We perform temperature and spatial dependent angle--resolved photoemission spectroscopy measurements through the…

We have found a ferromagnetic Weyl semimetal (WSM) in half metallic Co$_3$Sn$_2$Se$_2$. The three pairs of Weyl points near Fermi level (E$_F$) are derived from nodal lines gapped by spin-orbit coupling (SOC). Though the Weyl points are…

The recent discovery of the first Weyl semimetal in TaAs provides the first observation of a Weyl fermion in nature and demonstrates a novel type of anomalous surface state, the Fermi arc. Like topological insulators, the bulk topological…

Topological Weyl semimetal (TWS), a new state of quantum matter, has sparked enormous research interest recently. Possessing unique Weyl fermions in the bulk and Fermi arcs on the surface, TWSs offer a rare platform for realizing many…

The spin-orbit coupling (SOC) lifts the band degeneracy that plays a vital role in the search for different topological states, such as topological insulators (TIs) and topological semimetals (TSMs). In TSMs, the SOC can partially gap a…

Quantum topological materials, exemplified by topological insulators, three-dimensional Dirac semimetals and Weyl semimetals, have attracted much attention recently because of their unique electronic structure and physical properties. Very…

Ferromagnetic topological semimetals due to their band topology co-existing with intrinsic magnetization exerted important influences on early study of topological fermions. However, they have not been observed in experiments up to now. In…

Topological magnets exhibit fascinating properties like topologically protected surface states or anomalous transport phenomena. While these properties can be significantly altered by manipulating the magnetic state, the experimental…

Recent discovery of both gapped and gapless topological phases in weakly correlated electron systems has introduced various relativistic particles and a number of exotic phenomena in condensed matter physics. The Weyl fermion is a prominent…

Three-dimensional Dirac and Weyl semimetals have attracted widespread interest in condensed matter physics and material science. Here, based on first-principles calculations and symmetry analysis, we report that Ag$_2$S with…

Weyl semimetals are crystalline solids that host emergent relativistic Weyl fermions and have characteristic surface Fermi-arcs in their electronic structure. Weyl semimetals with broken time reversal symmetry are difficult to identify…

Nodal-line metals and semimetals, as interesting topological states of matter, have been mostly studied in nonmagnetic materials. Here, based on first-principles calculations and symmetry analysis, we predict that fully spin-polarized Weyl…

Magnetic Weyl semimetals (WSM) have recently attracted much attention due to their potential in realizing strong anomalous Hall effects. Yet, how to design such systems remains unclear. Based on first-principles calculations, we show here…

Engineering surfaces and interfaces of materials promises great potential in the field of heterostructures and quantum matter designer, with the opportunity of driving new many-body phases that are absent in the bulk compounds. Here, we…

Topological phases of matter exhibit phase transitions between distinct topological classes. These phase transitions are exotic in that they do not fall within the traditional Ginzburg-Landau paradigm but are instead associated with changes…