scholarly journals Evidence for dispersing 1D Majorana channels in an iron-based superconductor

Science ◽  
2020 ◽  
Vol 367 (6473) ◽  
pp. 104-108 ◽  
Author(s):  
Zhenyu Wang ◽  
Jorge Olivares Rodriguez ◽  
Lin Jiao ◽  
Sean Howard ◽  
Martin Graham ◽  
...  
Keyword(s):  
Bound States ◽  
Domain Walls ◽  
Lattice Structure ◽  
Condensed Matter ◽  
One Dimension ◽  
Scanning Tunneling ◽  
Majorana Fermions ◽  
Topological Phase ◽  
Linear Dispersion ◽  
Combined Data

The possible realization of Majorana fermions as quasiparticle excitations in condensed-matter physics has created much excitement. Most studies have focused on Majorana bound states; however, propagating Majorana states with linear dispersion have also been predicted. Here, we report scanning tunneling spectroscopic measurements of crystalline domain walls (DWs) in FeSe0.45Te0.55. We located DWs across which the lattice structure shifts by half a unit cell. These DWs have a finite, flat density of states inside the superconducting gap, which is a hallmark of linearly dispersing modes in one dimension. This signature is absent in DWs in the related superconductor, FeSe, which is not in the topological phase. Our combined data are consistent with the observation of dispersing Majorana states at a π-phase shift DW in a proximitized topological material.

scholarly journals Photoinduced multistage phase transitions in Ta2NiSe5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Q. M. Liu ◽  
D. Wu ◽  
Z. A. Li ◽  
L. Y. Shi ◽  
Z. X. Wang ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Lattice Structure ◽  
Condensed Matter ◽  
Electronic States ◽  
Excitation Intensity ◽  
Coherent Phonon ◽  
Optical Penetration Depth ◽  
Transmission Electron ◽  
Metal Phase Transition ◽  
Atom Displacement

AbstractUltrafast control of material physical properties represents a rapidly developing field in condensed matter physics. Yet, accessing the long-lived photoinduced electronic states is still in its early stages, especially with respect to an insulator to metal phase transition. Here, by combining transport measurement with ultrashort photoexcitation and coherent phonon spectroscopy, we report on photoinduced multistage phase transitions in Ta2NiSe5. Upon excitation by weak pulse intensity, the system is triggered to a short-lived state accompanied by a structural change. Further increasing the excitation intensity beyond a threshold, a photoinduced steady new state is achieved where the resistivity drops by more than four orders at temperature 50 K. This new state is thermally stable up to at least 350 K and exhibits a lattice structure different from any of the thermally accessible equilibrium states. Transmission electron microscopy reveals an in-chain Ta atom displacement in the photoinduced new structure phase. We also found that nano-sheet samples with the thickness less than the optical penetration depth are required for attaining a complete transition.

scholarly journals Universality of excited three-body bound states in one dimension

2021 ◽  
Author(s):  
Lucas Happ ◽  
Matthias Zimmermann ◽  
Maxim A Efremov
Keyword(s):  
Excited States ◽  
Bound States ◽  
Space Dimension ◽  
Binding Energies ◽  
Wave Functions ◽  
One Dimension ◽  
Strong Indication ◽  
Body System ◽  
Weakly Bound ◽  
Three Body

Abstract We study a heavy-heavy-light three-body system confined to one space dimension in the regime where an excited state in the heavy-light subsystems becomes weakly bound. The associated two-body system is characterized by (i) the structure of the weakly-bound excited heavy-light state and (ii) the presence of deeply-bound heavy-light states. The consequences of these aspects for the behavior of the three-body system are analyzed. We find a strong indication for universal behavior of both three-body binding energies and wave functions for different weakly-bound excited states in the heavy-light subsystems.

Ground state of one-dimension repulsing particles on disordered lattice

2014 ◽  
Vol 25 (08) ◽  
pp. 1450028 ◽  
Author(s):  
L. A. Pastur ◽  
V. V. Slavin ◽  
A. A. Krivchikov
Keyword(s):  
Ground State ◽  
Domain Walls ◽  
Host Lattice ◽  
One Dimension ◽  
Weak Disorder ◽  
Interacting Particles ◽  
One Dimensional ◽  
Lattice Disorder ◽  
Disordered Lattice ◽  
The Mean

The ground state (GS) of interacting particles on a disordered one-dimensional (1D) host-lattice is studied by a new numerical method. It is shown that if the concentration of particles is small, then even a weak disorder of the host-lattice breaks the long-range order of Generalized Wigner Crystal (GWC), replacing it by the sequence of blocks (domains) of particles with random lengths. The mean domains length as a function of the host-lattice disorder parameter is also found. It is shown that the domain structure can be detected by a weak random field, whose form is similar to that of the ground state but has fluctuating domain walls positions. This is because the generalized magnetization corresponding to the field has a sufficiently sharp peak as a function of the amplitude of fluctuations for small amplitudes.

Bound States in One Dimension

1994 ◽  
pp. 22-44
Author(s):  
Siegmund Brandt ◽  
Hans Dieter Dahmen
Keyword(s):  
Bound States ◽  
One Dimension

Bound States in One Dimension

1994 ◽  
pp. 22-43
Author(s):  
Siegmund Brandt ◽  
Hans Dieter Dahmen
Keyword(s):  
Bound States ◽  
One Dimension

scholarly journals Nanoscale strain engineering of giant pseudo-magnetic fields, valley polarization, and topological channels in graphene

2020 ◽  
Vol 6 (19) ◽  
pp. eaat9488 ◽  
Author(s):  
C.-C. Hsu ◽  
M. L. Teague ◽  
J.-Q. Wang ◽  
N.-C. Yeh
Keyword(s):  
Magnetic Fields ◽  
Domain Walls ◽  
Quantum Hall ◽  
Strain Engineering ◽  
Scanning Tunneling ◽  
Monolayer Graphene ◽  
Tunneling Microscopy ◽  
One Dimensional ◽  
Valley Polarization ◽  
Topological States

The existence of nontrivial Berry phases associated with two inequivalent valleys in graphene provides interesting opportunities for investigating the valley-projected topological states. Examples of such studies include observation of anomalous quantum Hall effect in monolayer graphene, demonstration of topological zero modes in “molecular graphene” assembled by scanning tunneling microscopy, and detection of topological valley transport either in graphene superlattices or at bilayer graphene domain walls. However, all aforementioned experiments involved nonscalable approaches of either mechanically exfoliated flakes or atom-by-atom constructions. Here, we report an approach to manipulating the topological states in monolayer graphene via nanoscale strain engineering at room temperature. By placing strain-free monolayer graphene on architected nanostructures to induce global inversion symmetry breaking, we demonstrate the development of giant pseudo-magnetic fields (up to ~800 T), valley polarization, and periodic one-dimensional topological channels for protected propagation of chiral modes in strained graphene, thus paving a pathway toward scalable graphene-based valleytronics.

Sign in / Sign up

Export Citation Format

Share Document