Flux Free Single Crystal Growth and Detailed Physical Property
Characterization of Bi1-xSbx (x = 0.05, 0.1 and 0.15) **Topological** **Insulator**

**topological**

**insulators**and their technological applications. Expand abstract.

**topological**

**insulator**. Single crystals of Bi1-xSbx (x = 0.05, 0.1 and 0.15) were grown by melting bismuth and antimony together using the facile self flux method. The XRD measurements displayed highly indexed 00l lines and confirmed the crystalline nature as well as the rhombohedral structure of the Bi1-xSbx (x = 0.05, 0.1 and 0.15) crystals. Raman spectroscopy measurements for Bi1-xSbx system revealed four peaks within the spectral range of 10 to 250 cm-1 namely A1g and Eg modes corresponding to Bi-Bi and Sb-Sb vibrations. Scanning electron microscopy (SEM) and energy dispersive Temperature dependent electrical resistivity curves with and without applied magnetic field exhibited a metallic behaviour and linear non-saturating magneto-resistance (MR) respectively for all the antimony (Sb) concentrations of x = 0.05, 0.1 and 0.15. The lowest Sb concentration sample with x = 0.05 (Bi0.95Sb0.05) exhibited the highest MR value of about 1400%, followed by x = 0.1 and 0.15 samples (Bi0.9Sb0.1 and Bi0.85Sb0.05) with MR values reaching up to 500% and 110% respectively at 2K and 6Tesla applied field. The magneto-conductivity (MC) is fitted to the HLN (Hikami Larkin Nagaoka) equation and it is found that the charge conduction mechanism is mainly dominated by WAL (weak anti-localization) along with a small contribution from WL (weak localization) effect. Summarily, the short letter discusses the synthesis, interesting transport and magneto-transport properties of Bi1-xSbx (x = 0.05, 0.1 and 0.15), which could be useful in understanding the fascinating properties of

**topological**

**insulators**and their technological applications.

10/10 relevant

arXiv

Odd-frequency superconductivity and Meissner effect in the doped
**topological** **insulator** Bi$_2$Se$_3$

5/10 relevant

arXiv

Theoretical investigation of the applicability of the Meservey-Tedrow
technique to the surface states of **topological** **insulators**

**topological**

**insulators**. Expand abstract.

**topological**surface states is of high interest for possible applications in spintronics. At present, the only technique capable to measure the surface state spin texture is spin and angle resolved photoemission spectroscopy (SARPES). However, values reported by SARPES differed strongly. An established technique to measure the spin polarization of ferromagnetic materials is the so-called Meservey-Tedrow technique, which is based on spin dependent tunneling from a superconducting electrode to a ferromagnet. Here, we theoretically investigate how the Meservey-Tedrow technique can be adapted to

**topological**

**insulators**. We demonstrate that with a specific device geometry it is possible to determine the in-plane component of the spin polarization of

**topological**surface states. More complex device geometries can access the full momentum dependence of the spin polarization. We also show that it is possible to extract the spin-flip scattering rate of surface electrons with the same devices.

10/10 relevant

arXiv

Floquet **topological** **insulators**: from band structure engineering to novel
non-equilibrium quantum phenomena

**topological**phases in many-body Floquet systems is their tendency to absorb energy from the drive and thereby to heat up. Expand abstract.

**topological**phenomena in quantum many-body systems. We discuss how such fields can be used to change the

**topological**properties of the single particle spectrum, and key experimental demonstrations in solid state, cold atomic, and photonic systems. The single particle Floquet band structure provides a stage on which the system's dynamics play out; the crucial question is then how to obtain robust

**topological**behaviour in the many-particle setting. In the regime of mesoscopic transport, we discuss manifestations of

**topological**edge states induced in the Floquet spectrum. Outside the context of mesoscopic transport, the main challenge of inducing stable

**topological**phases in many-body Floquet systems is their tendency to absorb energy from the drive and thereby to heat up. We discuss three routes to overcoming this challenge: long-lived transient dynamics and prethermalization, disorder-induced many-body localization, and engineered couplings to external baths. We discuss the types of phenomena that can be explored in each of these regimes, and their experimental realizations.

8/10 relevant

arXiv

Stability of dynamical quantum phase transitions in quenched **topological**
**insulators**: From multiband to disordered systems

**topological**

**insulators**and superconductors with disorder. Expand abstract.

**topological**properties. Here, we contribute to broadening the systematic understanding of this relation between topology and DQPTs to multi-orbital and disordered systems. Specifically, we provide a detailed ergodicity analysis to derive criteria for DQPTs in all spatial dimensions, and construct basic counter-examples to the occurrence of DQPTs in multi-band

**topological**

**insulator**models. As a numerical case study illustrating our results, we report on microscopic simulations of the quench dynamics in the Harper-Hofstadter model. Furthermore, going gradually from multi-band to disordered systems, we approach random disorder by increasing the (super) unit cell within which random perturbations are switched on adiabatically. This leads to an intriguing order of limits problem which we address by extensive numerical calculations on quenched one-dimensional

**topological**

**insulators**and superconductors with disorder.

10/10 relevant

arXiv

Single-Electron Transistor Made of a 3D **Topological** **Insulator** Nanoplate

**topological**

**insulators**have been proposed to be promising and of great importance for studies of confined

**topological**states and for applications in low energy-dissipative spintronics and quantum information processing. The absence of energy gap on the TI surface limits the experimental realization of a quantum confined system in three-dimensional

**topological**

**insulators**. This communication reports on the successful realization of single-electron transistor devices in Bi$_2$Te$_3$ nanoplates by state of the art nanofabrication techniques. Each device consists of a confined central island, two narrow constrictions that connect the central island to the source and drain, and surrounding gates. Low-temperature transport measurements demonstrate that the two narrow constrictions function as tunneling junctions and the device shows well-defined Coulomb current oscillations and Coulomb diamond shaped charge stability diagrams. This work provides a controllable and reproducible way to form quantum confined systems in three-dimensional

**topological**insulators, which should greatly stimulate research towards confined

**topological**states, low energy-dissipative devices and quantum information processing.

10/10 relevant

arXiv

Transport signatures of a Floquet **topological** transition at the helical
edge

**topological**

**insulators**is crucial for the development of technological applications. Expand abstract.

**topological**

**insulators**is crucial for the development of technological applications. Recently, an important step forward, namely, the experimental realization of a quantum point contact between helical edges, has been accomplished. We theoretically predict that such a quantum point contact, in the presence of a time periodic applied electric field, is characterized by a

**topological**quantum phase transition in the Floquet spectrum. Moreover, we show that it is possible to detect this dynamical

**topological**quantum phase transition by a bare conductance measurements.

4/10 relevant

arXiv

Josephson junction of finite-size superconductors on a **topological**
**insulator** under a magnetic field

**topological**

**insulator**under a magnetic field. At certain conditions, the junction hosts the chiral Majorana modes enclosing the two finite-size SCs. The interplay of the extended chiral Majorana modes and the states inside the junction can results in nontrivial

**topological**effects such as the $2n \pi$ fractional AC Josephson effects predicted in Ref.~\cite{ChoiSim} We show that the $2n \pi$ fractional AC Josephson effects can occur in a realistic situation, such as the presence of the midgap states, without requiring fine tuning of the parameters of the junction. We also find that the Shapiro spikes of the junction show a rich structure in a wide range of the AC voltage bias, facilitating experimental identification of the $2n \pi$ fractional AC Josephson effects. Moreover, we discuss how to observe the non-commutativity of the operations that braid the Majorana fermions of the junction, by measuring the Josephson current. Finally, we study the state evolution of the junction when the junction hosts a different number of Majorana zero modes from the case of the $2n \pi$ fractional AC Josephson effects.

7/10 relevant

arXiv

Higher-order **topological** **insulators** in a magnetic field

**topological**

**insulators**(HOTI). We investigate this model in a magnetic field which interpolates two models studied so far with zero flux and $\pi$ flux per plaquette. We show that in the Hofstadter butterfly there appears a wide gap around the $\pi$ flux, which belongs to the same HOTI discovered by Benalcazar-Bernevig-Hughes (BBH). It turns out that in a weak field regime HOTI could exist even within a small gap disconnected from the wider gap around $\pi$ flux. To characterize HOTI, we employ the entanglement polarization (eP) technique which is useful even if the basic four bands split into many Landau levels under a magnetic field.

10/10 relevant

arXiv

Large surface conductance and two-dimensional superconductivity in
microstructured crystalline **topological** **insulators**

**topological**

**insulator**Pb1-xSnxTe. Expand abstract.

**topological**electrical responses relevant to future applications such as quantum information science. Here we present microdevices fabricated with focused ion beam from indium-doped

**topological**

**insulator**Pb1-xSnxTe. With device thickness on the order of 1 {\mu}m and an extremely large bulk resistivity, we achieve an unprecedented enhancement of the surface contribution to about 30% of the total conductance near room temperature. The surface contribution increases as the temperature is reduced, becoming dominant below approximately 180 K, compared to 30 K in mm-thickness crystals. In addition to the enhanced surface contribution to normal-state transport, we observe the emergence of a two-dimensional superconductivity below 6 K. Measurements of magnetoresistivity at high magnetic fields reveal a weak antilocalization behavior in the normal-state magnetoconductance at low temperature and a variation in the power-law dependence of resistivity on temperature with field. These results demonstrate that interesting electrical response relevant to practical applications can be achieved by suitable engineering of single crystals.

10/10 relevant

arXiv