相关论文: Weak $\mathbb{Z}_2$ Supertopology

The two-dimensional (2D) surface state of the three-dimensional strong topological insulator (STI) is fundamentally distinct from other 2D electron systems in that the Fermi arc encircles an odd number of Dirac points. The TI surface is in…

Topological properties of materials, as manifested in the intriguing phenomena of quantum Hall effect and topological insulators, have attracted overwhelming transdisciplinary interest in recent years. Topological edge states, for instance,…

In two-dimensional crystals that lack symmetry under reflections on the horizontal plane of the lattice (non-$\sigma_{\rm h}$-symmetric), electrons can couple to flexural modes (ZA phonons) at first order. We show that in materials of this…

Topological materials in crystal solids, including topological insulators (TIs), topological crystalline insulators (TCIs), topological Dirac semimetals (DSMs), topological Weyl semimetals (WSMs), topological Dirac or Weyl nodal line…

In two-dimensional materials electronic band contacts often give non-trivial contribution to materials topological properties. Besides band contacts at high-symmetry points (HSP) in the Brillouin zone (BZ), like those in graphene, there are…

The interplay between topology and crystalline symmetries in materials can lead to a variety of topological crystalline insulator (TCI) states. Despite significant effort towards their experimental realization, so far only…

Usually, the octet rule has limited the 2D materials by elements within groups IIIA_VA, whose outmost electrons can be considered to form hybridization orbit by s wave and p wave. The hybridization orbits can accommodate all the outmost…

In non-magnetic bulk materials, inversion symmetry protects the spin degeneracy. If the bulk crystal structure lacks a centre of inversion, however, spin-orbit interactions lift the spin degeneracy, leading to a Rashba metal whose Fermi…

Conventional topological superconductors are fully gapped in the bulk but host gapless Majorana modes on their boundaries. We instead focus on a new class of superconductors, second-order topological superconductors, that have gapped,…

Based on first-principles calculations and symmetry analysis, we propose that a transition metal rutile oxide, in particular $\beta'$-PtO$_2$, can host a three-dimensional topological Dirac semimetal phase. We find that $\beta'$-PtO$_2$…

We prove theoretically that certain strongly correlated Kondo insulators are topological crystalline insulators with nontrivial topology protected by crystal symmetries. In particular, we find that SmB$_6$ is such a material. In addition to…

Spin waves (magnons) in 2D materials have received increasing interest due to their unique states and potential for tunability. However, many interesting features of these systems, including Dirac points and topological states, occur at…

The recent experimental confirmation of a transformation between meron and skyrmion topological spin textures in the chiral magnet Co$_8$Zn$_9$Mn$_3$ [S.-Z. Lin et al., Phys. Rev. B 91, 224407 (2015); X. Z. Yu et al., Nature 564, 95 (2018)]…

In a Dirac semimetal, the conduction and valence bands contact only at discrete (Dirac) points in the Brillouin zone (BZ) and disperse linearly in all directions around these critical points. Including spin, the low energy effective theory…

We use first principles calculations to study the electronic properties of rock salt rare earth monopnictides La$X$ ($X=$N, P, As, Sb, Bi). A new type of topological band crossing termed `linked nodal rings' is found in LaN when the small…

Advanced vector imaging techniques provide us with 3D maps of magnetization fields in which topological concepts can be directly applied to describe real-space experimental textures in non-ideal geometries. Here, the 3D magnetization of a…

The discovery of correlated phases in twisted moir\'e superlattices accelerated the search for low-dimensional materials with exotic properties. A promising approach uses engineered substrates to strain the material. However, designing…

Using density functional theory based calculations, we show that the correlated mixed-valent compound SmO is a 3D strongly topological semi-metal as a result of a 4$f$-5$d$ band inversion at the X point. The [001] surface Bloch spectral…

The non-centrosymmetric superconductors Li2Pd3B and Li2Pt3B show different superconducting properties despite having the same crystal symmetry. Motivated by experimental results, we investigate the spin susceptibility of non-centrosymmetric…

Until recently, spin-polarization in nonmagnetic materials was the exclusive territory of non- centrosymmetric structures. It was recently shown that a form of hidden spin polarization (named the Rashba-2 or R-2 effect) could exist in…