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We consider a junction between two topological insulators, and calculate the properties of the interface states with an effective low energy Hamiltonian for topological insulators with a single cone on the surface. This system bears a close…

Mesoscale and Nanoscale Physics · Physics 2013-03-14 Christophe De Beule , Bart Partoens

Topological insulators are transformative quantum solids with immune-to-disorder metallic surface states having Dirac band structure. Ubiquitous charged bulk defects, however, pull the Fermi energy into the bulk bands, denying access to…

Topological superconductors in one spatial dimension exhibiting a single Majorana bound state at each end are distinguished from trivial gapped systems by a Z_2 topological invariant. Originally, this invariant was calculated by Kitaev in…

Mesoscale and Nanoscale Physics · Physics 2013-08-15 Jan Carl Budich , Eddy Ardonne

We propose the concept of `topological Hamiltonian' for topological insulators and superconductors in interacting systems. The eigenvalues of topological Hamiltonian are significantly different from the physical energy spectra, but we show…

Strongly Correlated Electrons · Physics 2015-03-20 Zhong Wang , Binghai Yan

Different from previous scenarios that topological magnons emerge in local spin models, we propose an alternative that itinerant electron magnets can host topological magnons. A one-dimensional Tasaki model with a flat band is considered as…

Strongly Correlated Electrons · Physics 2018-06-13 Xiao-Fei Su , Zhao-Long Gu , Zhao-Yang Dong , Jian-Xin Li

Higher-order topological phases give rise to new bulk and boundary physics, as well as new classes of topological phase transitions. While the realization of higher-order topological phases has been confirmed in many platforms by detecting…

We report on a topological insulating state in a heavy-fermion system away from half-filling, which is hidden within a ferromagnetic metallic phase. In this phase, the cooperation of the RKKY interaction and the Kondo effect, together with…

Strongly Correlated Electrons · Physics 2013-04-16 Tsuneya Yoshida , Robert Peters , Satoshi Fujimoto , Norio Kawakami

Bilayer graphene encapsulated in tungsten diselenide can host a weak topological phase with pairs of helical edge states. The electrical tunability of this phase makes it an ideal platform to investigate unique topological effects at zero…

We discuss a topological classification of insulators and superconductors in the presence of both (non-spatial) discrete symmetries in the Altland-Zirnbauer classification and spatial reflection symmetry in any spatial dimensions. By using…

Mesoscale and Nanoscale Physics · Physics 2013-08-27 Ching-Kai Chiu , Hong Yao , Shinsei Ryu

We present a detailed investigation of the topological phases and Majorana fermion (MF) excitations that arise from the bulk interplay between (un)conventional one/two-band spin-singlet superconductivity and a number of magnetic texture…

Superconductivity · Physics 2022-03-28 Daniel Steffensen , Morten H. Christensen , Brian M. Andersen , Panagiotis Kotetes

An important characteristic of topological band insulators is the necessary presence of in-gap edge states on the sample boundary. We utilize this fact to show that when the boundary is reconnected with a twist, there are always zero-energy…

Strongly Correlated Electrons · Physics 2009-11-13 Dung-Hai Lee , Guang-Ming Zhang , Tao Xiang

Three-dimensional (3D) two-band Hopf insulators are a paradigmatic example of topological phases beyond the topological classifications based on powerful methods like $K$-theory and symmetry indicators.Since this class of topological…

Mesoscale and Nanoscale Physics · Physics 2023-02-06 Zhu Wang , Xu-Tao Zeng , Yuanchuan Biao , Zhongbo Yan , Rui Yu

We demonstrate that a combination of disorder and interactions in a two-dimensional bulk topological insulator can generically drive its helical edge insulating. We establish this within the framework of helical Luttinger liquid theory and…

Strongly Correlated Electrons · Physics 2018-08-24 Yang-Zhi Chou , Rahul M. Nandkishore , Leo Radzihovsky

The topological properties in topological superconductors are usually characterized by the bulk Chern numbers, edge-state spectra, and Majorana zero modes. Whether they are equivalent or inequivalent is not well understood. Here, we…

Mesoscale and Nanoscale Physics · Physics 2017-10-03 Xiao-Ping Liu , Yuan Zhou , Yi-Fei Wang , Chang-De Gong

In a flat band superconductor, bosonic excitations can disperse while unpaired electrons are immobile. To study this strongly interacting system, we construct a family of multi-band Hubbard models with exact eta-pairing ground states in all…

Strongly Correlated Electrons · Physics 2022-09-02 Jonah Herzog-Arbeitman , Aaron Chew , Kukka-Emilia Huhtinen , Päivi Törmä , B. Andrei Bernevig

The extension of the topological classification of band insulators to topological semimetals gave way to the topology classes of Dirac, Weyl, and nodal line semimetals with their unique Fermi arc and drum head boundary modes. Similarly,…

The concept of free fermion topology has been generalized to $d$-dimensional phases that exhibit $(d-n)$-dimensional boundary modes, such as zero-dimensional (0D) corner excitations. Motivated by recent extensions of these ideas to magnetic…

Strongly Correlated Electrons · Physics 2023-12-22 Arijit Haldar , Geremia Massarelli , Arun Paramekanti

Topological insulators are new quantum states with helical gapless edge or surface states inside the bulk band gap.These topological surface states are robust against the weak time-reversal invariant perturbations, such as lattice…

Mesoscale and Nanoscale Physics · Physics 2013-08-07 Haijun Zhang , Shou-Cheng Zhang

In this paper we find that confining a second-order topological superconductor with a harmonic potential leads to a proliferation of Majorana corner modes. As a consequence, this results in the formation of Majorana corner flat bands which…

Superconductivity · Physics 2020-03-05 Majid Kheirkhah , Yuki Nagai , Chun Chen , Frank Marsiglio

We investigate the ground-state phase diagram of a modified spinless Haldane-Hubbard model with broken threefold rotational symmetry, employing exact diagonalization calculations. The interplay of asymmetry, interactions, and topology gives…

Strongly Correlated Electrons · Physics 2023-05-03 Tian-Cheng Yi , Hai-Qing Lin , Rubem Mondaini