In-plane noncollinear exchange coupling mediated by helical edge states in quantum spin Hall systems

Gao, Jin-Hua; Chen, Wei-Qiang; Xie, X. C.; Zhang, Fuchun

doi:10.1103/physrevb.80.241302

Cited by 35 publications

(29 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These helical fermion states only have two degrees of freedom; the spin polarization is correlated with the direction of motion. A mass term, being proportional to the Pauli matrices σ 1,2,3 , can only be introduced in the Hamiltonian by coupling to a TR symmetry breaking external field such as a magnetic field, aligned magnetic impurities (Gao et al, 2009), or interaction-driven ferromagnetic order on the edge (Kharitonov, 2010). To leading order in perturbation theory, a magnetic field generates the mass terms…”

Section: Fractional Charge On the Edgementioning

confidence: 99%

Topological insulators and superconductors

2011

View full text Add to dashboard Cite

Topological insulators are new states of quantum matter which can not be adiabatically connected to conventional insulators and semiconductors. They are characterized by a full insulating gap in the bulk and gapless edge or surface states which are protected by time-reversal symmetry. These topological materials have been theoretically predicted and experimentally observed in a variety of systems, including HgTe quantum wells, BiSb alloys, and Bi 2 Te 3 and Bi 2 Se 3 crystals. We review theoretical models, materials properties and experimental results on two-dimensional and three-dimensional topological insulators, and discuss both the topological band theory and the topological field theory. Topological superconductors have a full pairing gap in the bulk and gapless surface states consisting of Majorana fermions. We review the theory of topological superconductors in close analogy to the theory of topological insulators.

show abstract

Section: Fractional Charge On the Edgementioning

confidence: 99%

Topological insulators and superconductors

2011

View full text Add to dashboard Cite

show abstract

“…From an experimental point of view, impurities are not necessarily isolated and interimpurity coherence effects might play an important role in transport properties at low temperatures. From a theoretical point of view, one expects that effective interactions of the Ruderman-Kittel-Kasuya-Yosida (RKKY) type will be mediated between quantum impurities by the helical edge electrons, 32 and it is natural to ask what particular quantum phases will be formed by a collection of quantum impurities under the influence of such interactions.…”

Section: -31mentioning

confidence: 99%

“…On the other hand, if one were to integrate out the conduction electron field φ in Eq. (31), one would generate long-range RKKY-type spin-spin interaction terms 32 of the form…”

Section: A Decoupling Limitmentioning

confidence: 99%

Kondo lattice on the edge of a two-dimensional topological insulator

Maciejko

2012

Phys. Rev. B

View full text Add to dashboard Cite

We revisit the problem of a single quantum impurity on the edge of a two-dimensional timereversal invariant topological insulator and show that the zero temperature phase diagram contains a large local moment region for antiferromagnetic Kondo coupling which was missed by previous poor man's scaling treatments. The combination of an exact solution at the so-called decoupling point and a renormalization group analysisà la Anderson-Yuval-Hamann allows us to access the regime of strong electron-electron interactions on the edge and strong Kondo coupling. We apply similar methods to the problem of a regular one-dimensional array of quantum impurities interacting with the edge liquid. When the edge electrons are at half-filling with respect to the impurity lattice, the system remains gapless unless the Luttinger parameter of the edge is less than 1/2, in which case two-particle backscattering effects drive the system to a gapped phase with long-range Ising antiferromagnetic order. This is in marked contrast with the gapped disordered ground state of the ordinary half-filled one-dimensional Kondo lattice.

show abstract

“…Additional spintronic functionalities can be expected from introducing ferromagnetic impurities, which are suggested to break time-reversal symmetry, thereby opening a gap in the TSS. This is of interest for devices, such as transistors, as well as for achieving the quantum anomalous Hall state [10][11][12][13][14][15][16][17] . However, their experimental realization has proven challenging and has led to yet another controversy in the literature, i.e., whether adding ferromagnetic impurities in a TI can indeed open a band gap in the TSS [18][19][20][21][22][23][24][25][26] .…”

Section: Introductionmentioning

confidence: 99%

Topological surface state of α−Sn on InSb(001) as studied by photoemission

et al. 2018

View full text Add to dashboard Cite

We report on the electronic structure of the elemental topological semimetal α-Sn on InSb(001). High-resolution angle-resolved photoemission data allow to observe the topological surface state (TSS) that is degenerate with the bulk band structure and show that the former is unaffected by different surface reconstructions. An unintentional p-type doping of the as-grown films was compensated by deposition of potassium or tellurium after the growth, thereby shifting the Dirac point of the surface state below the Fermi level. We show that, while having the potential to break time-reversal symmetry, iron impurities with a coverage of up to 0.25 monolayers do not have any further impact on the surface state beyond that of K or Te. Furthermore, we have measured the spin-momentum locking of electrons from the TSS by means of spin-resolved photoemission. Our results show that the spin vector lies fully in-plane, but it also has a finite radial component. Finally, we analyze the decay of photoholes introduced in the photoemission process, and by this gain insight into the many-body interactions in the system. Surprisingly, we extract quasiparticle lifetimes comparable to other topological materials where the TSS is located within a bulk band gap. We argue that the main decay of photoholes is caused by intraband scattering, while scattering into bulk states is suppressed due to different orbital symmetries of bulk and surface states.

show abstract

In-plane noncollinear exchange coupling mediated by helical edge states in quantum spin Hall systems

Cited by 35 publications

References 27 publications

Topological insulators and superconductors

Topological insulators and superconductors

Kondo lattice on the edge of a two-dimensional topological insulator

Topological surface state of α−Sn on InSb(001) as studied by photoemission

Contact Info

Product

Resources

About