scholarly journals Quantum oscillations of robust topological surface states up to 50 K in thick bulk-insulating topological insulator

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Weiyao Zhao ◽  
Lei Chen ◽  
Zengji Yue ◽  
Zhi Li ◽  
David Cortie ◽  
...  
Keyword(s):  
Single Crystal ◽  
Electronic Devices ◽  
Surface States ◽  
Maximum Temperature ◽  
Dirac Fermions ◽  
Transport Behavior ◽  
Low Dissipation ◽  
Clear Sign ◽  
Key Factor ◽  
Sdh Oscillations

Abstract As personal electronic devices increasingly rely on cloud computing for energy-intensive calculations, the power consumption associated with the information revolution is rapidly becoming an important environmental issue. Several approaches have been proposed to construct electronic devices with low-energy consumption. Among these, the low-dissipation surface states of topological insulators (TIs) are widely employed. To develop TI-based devices, a key factor is the maximum temperature at which the Dirac surface states dominate the transport behavior. Here, we employ Shubnikov-de Haas oscillations (SdH) as a means to study the surface state survival temperature in a high-quality vanadium doped Bi1.08Sn0.02Sb0.9Te2S single crystal system. The temperature and angle dependence of the SdH show that: (1) crystals with different vanadium (V) doping levels are insulating in the 3–300 K region; (2) the SdH oscillations show two-dimensional behavior, indicating that the oscillations arise from the pure surface states; and (3) at 50 K, the V0.04 single crystals (Vx:Bi1.08-xSn0.02Sb0.9Te2S, where x = 0.04) still show clear sign of SdH oscillations, which demonstrate that the surface dominant transport behavior can survive above 50 K. The robust surface states in our V doped single crystal systems provide an ideal platform to study the Dirac fermions and their interaction with other materials above 50 K.

Magnetic Quantum Oscillations from Surface States of Bi Nanowires

2011 ◽  
Vol 1350 ◽  
Author(s):  
L. A. Konopko ◽  
T. E. Huber ◽  
A. A. Nikolaeva
Keyword(s):  
Single Crystal ◽  
Low Temperatures ◽  
Surface States ◽  
Charge Carriers ◽  
Quantum Oscillations ◽  
Wide Range ◽  
Spin Orbit Interactions ◽  
Conducting Tube ◽  
Magnetic Quantum Oscillations ◽  
Strong Spin

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.

Performance Comparison of Microchannel Heat Sink Using Boron-Based Ceramic Materials

2021 ◽  
Vol 1163 ◽  
pp. 73-88
Author(s):  
Md Tanbir Sarowar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Sink ◽  
Electronic Devices ◽  
Ceramic Materials ◽  
Substrate Material ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Microchannel Heat Sink ◽  
Small Surface

Microchannel heat sink plays a vital role in removing a considerable amount of heat flux from a small surface area from different electronic devices. In recent times, the rapid development of electronic devices requires the improvement of these heat sinks to a greater extent. In this aspect, the selection of appropriate substrate materials of the heat sinks is of vital importance. In this paper, three boron-based ultra-high temperature ceramic materials (ZrB2, TiB2, and HfB2) are compared as a substrate material for the microchannel heat sink using a numerical approach. The fluid flow and heat transfer are analyzed using the finite volume method. The results showed that the maximum temperature of the heat source didn’t exceed 355K at 3.6MWm-2 for any material. The results also indicated HfB2 and TiB2 to be more useful as a substrate material than ZrB2. By applying 3.6 MWm-2 heat flux at the source, the maximum obtained surface heat transfer coefficient was 175.2 KWm-2K-1 in a heat sink having substrate material HfB2.

scholarly journals Degradation of Cu nanowires in a low-reactive plasma environment

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Diego S. R. Coradini ◽  
Matheus A. Tunes ◽  
Thomas M. Kremmer ◽  
Claudio G. Schön ◽  
Peter J. Uggowitzer ◽  
...  
Keyword(s):  
Single Crystal ◽  
Electronic Devices ◽  
Processing Conditions ◽  
Cu Nanowires ◽  
Plasma Environment ◽  
Mechanical And Electrical Properties ◽  
Reactive Plasma ◽  
Synthesis And Processing ◽  
Solid Nucleation ◽  
Nucleation And Growth Mechanism

Abstract The quest for miniaturisation of electronic devices is one of the backbones of industry 4.0 and nanomaterials are an envisaged solution capable of addressing these complex technological challenges. When subjected to synthesis and processing, nanomaterials must be able to hold pristine its initial designed properties, but occasionally, this may trigger degradation mechanisms that can impair their application by either destroying their initial morphology or deteriorating of mechanical and electrical properties. Degradation of nanomaterials under processing conditions using plasmas, ion implantation and high temperatures is up to date largely sub-notified in the literature. The degradation of single-crystal Cu nanowires when exposed to a plasma environment with residual active O is herein investigated and reported. It is shown that single-crystal Cu nanowires may degrade even in low-reactive plasma conditions by means of a vapour–solid–solid nucleation and growth mechanism.

Single Crystalline 4H-SiC MEMS Devices with N-P-N Epitaxial Structure

2014 ◽  
Vol 1693 ◽  
Author(s):  
Feng Zhao ◽  
Allen Lim ◽  
Zhibang Chen ◽  
Chih-Fang Huang
Keyword(s):  
Single Crystal ◽  
Electronic Devices ◽  
Device Fabrication ◽  
Flat Band ◽  
Harsh Environment ◽  
Mems Devices ◽  
Etching Technique ◽  
Epitaxial Structure ◽  
Single Crystal Sic ◽  
P Type

ABSTRACTIn this paper, single crystal 4H-SiC MEMS devices with n-p-n epitaxial structure was fabricated. A dopant-selective photoelectrochemical etching technique was applied to etch the sacrificial p-type SiC layer to release n-type SiC suspended structures on n-type SiC substrate. The selective etching was achieved by applying a bias which employs the different flat-band potentials of n-SiC and p-SiC in KOH solution. Such MEMS devices have the potential to fully exploit the superior properties of single crystal SiC for harsh environment operation, as well as mature epitaxial growth and device fabrication of 4H-SiC. The n-p-n structure, together with the previously reported p-n structure, extends the capability of monolithic integration between MEMS with electronic devices and circuits on SiC platform.

Topological Surface States of Dirac Fermions in n-Bi2Te3 –ySey Thermoelectrics

2019 ◽  
Vol 53 (5) ◽  
pp. 647-651
Author(s):  
L. N. Lukyanova ◽  
I. V. Makarenko ◽  
O. A. Usov ◽  
P. A. Dementev
Keyword(s):  
Surface States ◽  
Dirac Fermions ◽  
Topological Surface

Synthesis and Properties of Cellulose Stearate

2011 ◽  
Vol 228-229 ◽  
pp. 919-924 ◽  
Author(s):  
Feng Yuan Huang
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Glass Transition ◽  
Transition Temperature ◽  
1H Nmr ◽  
Homogeneous System ◽  
Molar Ratio ◽  
Maximum Temperature ◽  
Key Factor ◽  
Ft Ir

Cellulose Stearate (CS) was synthesized by acylating microcrystalline cellulose (MCC) in homogeneous system with p-toluenesulfonyl chloride (Tos-Cl) and stearic acid (SA). The reactive conditions were discussed. The molar ratio of AGU:SA:Tos-Cl was the key factor which affected the degree of substitution (DS) of CS. In the present paper, CSs with DS ranging from 0.64 to 2.35 were prepared under mild condition. The structure of CS was characterized by FT-IR and 1H-NMR, and DS of CS was determined by traditional saponification method and 1H-NMR, respectively. The solubility of CS was also investigated; the results showed that the higher DS of CS was, the easier CS dissolved in organic solvents. The thermal analysis was measured with DSC, and the results indicated that the glass transition temperature (Tg) and the maximum temperature of thermal decomposition (Tmax) of CS were dependent on DS.

scholarly journals Irradiated cubic single crystal SiC as a high temperature sensor

2003 ◽  
Vol 792 ◽  
Author(s):  
Alex A. Volinsky ◽  
Lev Ginzbursky
Keyword(s):  
Single Crystal ◽  
Film Growth ◽  
Space Shuttle ◽  
Turbine Blades ◽  
Maximum Temperature ◽  
X Ray Diffraction ◽  
Ceramic Tiles ◽  
X Ray ◽  
Single Crystal Sic ◽  
Technology Modeling

ABSTRACTRadiation is known to cause point defects formation in different materials. In the case of cubic SiC single crystal radiation flux on the order of 2·1020 neutrons/cm2 at 0.18 MeV causes over 3% volume lattice expansion. Radiation-induced strain (measurable by X-Ray diffraction) can be relieved when the annealing temperature exceeds the temperature of irradiation. Based on this effect the original technology of maximum temperature measurement was developed a while ago. Single crystal SiC sensor small size (200–500 microns), wide temperature range (150–1450 °C), “no-lead” installation, and exceptional accuracy make it very attractive for use in small, rotating and “hard-to-access” parts, including, but not limited to gas turbine blades, space shuttle ceramic tiles, automobile engines, etc. With the advances in X-Ray diffraction measurements, crystal and thin film growth techniques, it is the time to revise and update this technology. Modeling radiation damage, as well as annealing effects are also beneficial.

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