Magnetic Quantum Oscillations from Surface States of Bi Nanowires

ABSTRACTIn this work, we report the results of studies of the transverse magnetoresistance (MR) of single-crystal Bi nanowires with diameter d<80 nm. The single-crystal nanowire samples were prepared by the Taylor-Ulitovsky technique. Due to the semimetal-to-semiconductor transformation and high density of surface states with strong spin-orbit interactions, the charge carriers are confined to the conducting tube made of surface states. The non monotonic changes of transverse MR that are equidistant in a direct magnetic field were observed at low temperatures in a wide range of magnetic fields up to 14 T. The period of oscillations depends on the wire diameter d as for the case of longitudinal MR. An interpretation of transverse MR oscillations is presented.

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QUANTUM OSCILLATIONS, TUNNELING MAGNETORESISTANCE AND ANGULAR DEPENDENCE OF MAGNETIZATION IN Ca3Ru2O7

International Journal of Modern Physics B ◽

10.1142/s0217979202014097 ◽

2002 ◽

Vol 16 (20n22) ◽

pp. 3251-3251

Author(s):

G. CAO

Keyword(s):

Angular Dependence ◽

Metallic Phase ◽

Tunneling Magnetoresistance ◽

Electronic Transitions ◽

Orthorhombic Structure ◽

Quantum Oscillations ◽

Antiferromagnetic Ordering ◽

Wide Range ◽

Spin Charge Coupling ◽

Strong Spin

Ca3Ru2O7 has a double Ru-O layered orthorhombic structure. It is a "bad" metal characterized by various abrupt magnetic and electronic transitions that are highly anisotropic. Ca3Ru2O7 undergoes antiferromagnetic ordering at TN = 56 K and a metal to poorer metal transition at TM = 48 K with a unique antiferromagnetic metallic phase intermediate between the paramagnetic and antiferromagnetic phases. Our recent study reveals a few more striking features: (1) Quantum oscillations, i.e., the Shubnikov-de Haas effect, of which the fast Fourier transform shows two frequencies F1 = 23.4 and F2 = 41 tesla, respectively; (2) Inter-plane tunneling magnetoresistance, whose ratio is more than 90% [ρ(0) - ρ(H)/ρ(0)]; (3) Anomalous angular dependence of magnetization, which leads to similar angular dependence of resistivity due to a strong spin-charge coupling. Ca3Ru2O7 is a rare system that possesses a wide range of interesting yet complex physical properties that very often do not coexist in other materials. The results and discussions will be presented along with comparisons with other related systems.

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Magnetic quantum oscillations for the surface states of topological insulatorBi2Se3

Physical Review B ◽

10.1103/physrevb.82.085429 ◽

2010 ◽

Vol 82 (8) ◽

Cited By ~ 30

Author(s):

Zhigang Wang ◽

Zhen-Guo Fu ◽

Shuang-Xi Wang ◽

Ping Zhang

Keyword(s):

Surface States ◽

Quantum Oscillations ◽

Magnetic Quantum Oscillations

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Thermoelectric Characteristics of A Single-Crystalline Topological Insulator Bi2Se3 Nanowire

Nanomaterials ◽

10.3390/nano11030819 ◽

2021 ◽

Vol 11 (3) ◽

pp. 819

Author(s):

Dedi ◽

Ping-Chung Lee ◽

Pai-Chun Wei ◽

Yang-Yuan Chen

Keyword(s):

Thermoelectric Properties ◽

Figure Of Merit ◽

Surface States ◽

Volume Ratio ◽

Single Crystalline ◽

Transmission Electron ◽

Growth Method ◽

Spin Orbit Interactions ◽

Good Agreement ◽

Strong Spin

The discovery of topological insulators (TIs) has motivated detailed studies on their physical properties, especially on their novel surface states via strong spin–orbit interactions. However, surface-state-related thermoelectric properties are rarely reported, likely because of the involvement of their bulk-dominating contribution. In this work, we report thermoelectric studies on a TI bismuth selenide (Bi2Se3) nanowire (NW) that exhibit a larger surface/volume ratio. Uniform single-crystalline TI Bi2Se3 NWs were successfully synthesized using a stress-induced growth method. To achieve the study of the thermoelectric properties of a nanowire (NW), including electrical conductivity (σ), Seebeck coefficient (S), and thermal conductivity (κ), a special platform for simultaneously performing all measurements on a single wire was designed. The properties of σ, S, and κ of a 200 nm NW that was well precharacterized using transmission electron microscope (TEM) measurements were determined using the four-probe method, the two-probe EMF across ∇T measurement, and the 3ω technique, respectively. The integrated TE properties represented by the figure of merit ZT (S2σT/κ) were found to be in good agreement with a theoretical study of Bi2Se3 NW.

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Гальваномагнитные свойства в анизотропных слоистых пленках на основе халькогенидов висмута

Физика и техника полупроводников ◽

10.21883/ftp.2021.12.51692.08 ◽

2021 ◽

Vol 55 (12) ◽

pp. 1119

Author(s):

О.А. Усов ◽

Л.Н. Лукьянова ◽

М.П. Волков

Keyword(s):

Low Temperatures ◽

High Surface ◽

Surface States ◽

Surface Concentration ◽

Dirac Fermion ◽

Quantum Oscillations ◽

Strong Magnetic Fields ◽

High Surface Concentration ◽

Comparison Of The Results ◽

Tunnel Spectroscopy

In anisotropic layered films of a multicomponent n-Bi1.92In0.02Te2.85Se0.15 solid solution in strong magnetic fields from 2 to 14 T at low temperatures, quantum oscillations of magnetoresistance associated with surface states of electrons in 3D topological insulators were studied. From the analysis of the spectral distribution of the amplitudes of quantum oscillations of magnetoresistance, the main parameters of the Dirac fermion surface states are determined. A comparison of the results with the data obtained by the method of scanning tunnel spectroscopy was carried out. It is shown that a high surface concentration determines the contribution of the Dirac fermion surface states to the thermoelectric properties of n-Bi1.92In0.02Te2.85Se0.15.

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Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009292x ◽

1976 ◽

Vol 34 ◽

pp. 592-593

Author(s):

Ernest L. Hall ◽

J. B. Vander Sande

Keyword(s):

Mechanical Properties ◽

Single Crystal ◽

Dislocation Structure ◽

Room Temperature ◽

Elevated Temperatures ◽

Strain Curve ◽

Optical Devices ◽

Semiconductor Compound ◽

Wide Range ◽

Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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Epitaxial ferroelectric thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170591 ◽

1994 ◽

Vol 52 ◽

pp. 572-573

Author(s):

S. G. Ghonge ◽

E. Goo ◽

R. Ramesh ◽

R. Haakenaasen ◽

D. K. Fork

Keyword(s):

Single Crystal ◽

Work Function ◽

Nonvolatile Memory ◽

Ferroelectric Properties ◽

Electrical Contact ◽

Memory Devices ◽

Ferroelectric Films ◽

Si Substrates ◽

Electro Optic ◽

Wide Range

Microstructure of epitaxial ferroelectric/conductive oxide heterostructures on LaAIO3(LAO) and Si substrates have been studied by conventional and high resolution transmission electron microscopy. The epitaxial films have a wide range of potential applications in areas such as non-volatile memory devices, electro-optic devices and pyroelectric detectors. For applications such as electro-optic devices the films must be single crystal and for applications such as nonvolatile memory devices and pyroelectric devices single crystal films will enhance the performance of the devices. The ferroelectric films studied are Pb(Zr0.2Ti0.8)O3(PLZT), PbTiO3(PT), BiTiO3(BT) and Pb0.9La0.1(Zr0.2Ti0.8)0.975O3(PLZT).Electrical contact to ferroelectric films is commonly made with metals such as Pt. Metals generally have a large difference in work function compared to the work function of the ferroelectric oxides. This results in a Schottky barrier at the interface and the interfacial space charge is believed to responsible for domain pinning and degradation in the ferroelectric properties resulting in phenomenon such as fatigue.

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