scholarly journals Electrically controlled spin polarized current in Dirac semimetals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qianqian Lv ◽  
Pei-Hao Fu ◽  
Xiang-Long Yu ◽  
Jun-Feng Liu ◽  
Jiansheng Wu
Keyword(s):  
Coupling Strength ◽  
Gate Voltage ◽  
Chemical Potential ◽  
Density Of State ◽  
Electrical Parameters ◽  
Spintronic Device ◽  
Dirac Semimetal ◽  
Fermi Arcs ◽  
Spin Polarized ◽  
Dirac Semimetals

AbstractWe propose a highly tunable $$100\%$$ 100 % spin-polarized current generated in a spintronic device based on a Dirac semimetal (DSM) under a magnetic field, which can be achieved merely by controlling electrical parameters, i.e. the gate voltage, the chemical potential in the lead and the coupling strength between the leads and the DSM. These parameters are all related to the special properties of a semimetal. The spin polarized current generated by gate voltage is guaranteed by its semimetallic feature, because of which the density of state vanishes near Dirac nodes. The barrier controlled current results from the different distance of Weyl nodes generated by the Zeeman field. And the coupling strength controlled spin polarized current originates from the surface Fermi arcs. This DSM-based spintronic device is expected to be realized in $$\hbox {Cd}_{3}\hbox {As}_{2}$$ Cd 3 As 2 experimentally.

scholarly journals Electrically controlled spin polarized current in Dirac semimetals

2021 ◽  
Author(s):  
Qianqian Lv ◽  
Pei-Hao Fu ◽  
Xiang-Long Yu ◽  
Jun-Feng Liu ◽  
Jiansheng Wu
Keyword(s):  
Coupling Strength ◽  
Gate Voltage ◽  
Density Of State ◽  
Spintronic Devices ◽  
Dirac Semimetal ◽  
Weyl Semimetal ◽  
Fermi Arcs ◽  
Spin Polarized ◽  
Electric Parameters ◽  
Spintronics Device

Abstract We propose a highly tunable 100% spin-polarized current generated in a spintronics device based on Dirac semimetal under a magnetic field, which can be achieved merely by controlling electric parameters, i.e. the gate voltage, the barrier in the lead and the coupling strength between the leads and Dirac semimetal. These parameters are all related to the special properties of Dirac semimetal and Weyl semimetal. The spin polarized current generated by gate voltage is guaranteed by its semimetallic feature, because of which the density of state vanishes near Dirac nodes. The barrier controlled current results from the different distance of Weyl nodes generated by the Zeeman field. And the coupling strength controlled spin polarized current originate from the surface Fermi arcs. All these features make a great potential to realized Dirac semimetal based spintronic devices.

scholarly journals Are the surface Fermi arcs in Dirac semimetals topologically protected?

2016 ◽  
Vol 113 (31) ◽  
pp. 8648-8652 ◽  
Author(s):  
Mehdi Kargarian ◽  
Mohit Randeria ◽  
Yuan-Ming Lu
Keyword(s):  
Chemical Potential ◽  
Surface States ◽  
Quantum Oscillation ◽  
Band Model ◽  
Fermi Surfaces ◽  
Space Groups ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Fermi Arcs ◽  
Anomalous Surface ◽  
Dirac Semimetals

Motivated by recent experiments probing anomalous surface states of Dirac semimetals (DSMs) Na3Bi and Cd3As2, we raise the question posed in the title. We find that, in marked contrast to Weyl semimetals, the gapless surface states of DSMs are not topologically protected in general, except on time-reversal-invariant planes of surface Brillouin zone. We first demonstrate this finding in a minimal four-band model with a pair of Dirac nodes at k=(0,0,±Q), where gapless states on the side surfaces are protected only near kz=0. We then validate our conclusions about the absence of a topological invariant protecting double Fermi arcs in DSMs, using a K-theory analysis for space groups of Na3Bi and Cd3As2. Generically, the arcs deform into a Fermi pocket, similar to the surface states of a topological insulator, and this pocket can merge into the projection of bulk Dirac Fermi surfaces as the chemical potential is varied. We make sharp predictions for the doping dependence of the surface states of a DSM that can be tested by angle-resolved photoemission spectroscopy and quantum oscillation experiments.

scholarly journals Half-Dirac Semimetal and Quantum Anomalous Hall Effect in Kagome Cd2N3 Lattice

2020 ◽  
Author(s):  
Xinyang Li ◽  
Weixiao Ji ◽  
Peiji Wang ◽  
Chang-wen Zhang
Keyword(s):  
Hall Effect ◽  
Quantum State ◽  
Anomalous Hall Effect ◽  
Topological Phases ◽  
Dirac Semimetal ◽  
Quantum Anomalous Hall Effect ◽  
Dirac Materials ◽  
Low Dimensionality ◽  
Dirac Semimetals ◽  
Topological Phases Of Matter

Half-Dirac semimetals (HDSs), which possess 100% spin-polarizations for Dirac materials, are highly desirable for exploring various topological phases of matter, as low-dimensionality opens unprecedented opportunities for manipulating the quantum state...

scholarly journals Prediction of spin polarized Fermi arcs in quasiparticle interference in CeBi

2020 ◽  
Vol 102 (23) ◽  
Author(s):  
Zhao Huang ◽  
Christopher Lane ◽  
Chao Cao ◽  
Guo-Xiang Zhi ◽  
Yu Liu ◽  
...  
Keyword(s):  
Quasiparticle Interference ◽  
Fermi Arcs ◽  
Spin Polarized

scholarly journals Tunable Berry curvature and transport crossover in topological Dirac semimetal KZnBi

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Junseong Song ◽  
Byung Cheol Park ◽  
Kyung Ik Sim ◽  
Joonho Bang ◽  
Sunghun Kim ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Hall Resistance ◽  
Rotational Axis ◽  
Material System ◽  
Chiral Fermion ◽  
Quantum Phases ◽  
Berry Curvature ◽  
Dirac Semimetal ◽  
Dirac Semimetals ◽  
Single Material

AbstractTopological Dirac semimetals have emerged as a platform to engineer Berry curvature with time-reversal symmetry breaking, which allows to access diverse quantum states in a single material system. It is of interest to realize such diversity in Dirac semimetals that provides insight on correlation between Berry curvature and quantum transport phenomena. Here, we report the transition between anomalous Hall and chiral fermion states in three-dimensional topological Dirac semimetal KZnBi, which is demonstrated by tuning the direction and flux of Berry curvature. Angle-dependent magneto-transport measurements show that both anomalous Hall resistance and positive magnetoresistance are maximized at 0° between net Berry curvature and rotational axis. We find that the unexpected crossover of anomalous Hall resistance and negative magnetoresistance suddenly occurs when the angle reaches to ~70°, indicating that Berry curvature strongly correlates with quantum transports of Dirac and chiral fermions. It would be interesting to tune Berry curvature within other quantum phases such as topological superconductivity.

ELECTRICAL CONDUCTANCE OF ZIGZAG NANOGRAPHITE RIBBONS WITH LOCALLY APPLIED GATE VOLTAGE

2002 ◽  
Vol 16 (32) ◽  
pp. 4897-4909 ◽  
Author(s):  
KATSUNORI WAKABAYASHI ◽  
TAKASHI AOKI
Keyword(s):  
Gate Voltage ◽  
Chemical Potential ◽  
Single Channel ◽  
Energy Gap ◽  
Electrical Conductance ◽  
Transmission Probability ◽  
Edge States ◽  
Transport Channel ◽  
Electric Conductance ◽  
Voltage Bias

The electric conductance of the graphite ribbon with locally applied gate voltage has been studied in terms of the Landauer approach. In the low-energy region, nano-graphite ribbon with zigzag boundaries exhibits the single electronic transport channel due to the edge states. The chemical potential dependence of the electric conductance shows qualitatively different behavior, depending on whether the magnitude of the potential barrier (gate voltage bias) Vg is larger than the energy gap Δ of the single channel region of the zigzag ribbon. For positive Vg with Vg < Δ, the zero-conductance resonances appear for 0 ≤ E ≤ Vg, and average transmission probability is quite small in this region. However the transmission probability is almost one, i.e. perfect transmission, for E > Vg. This step-function-like behavior of the conductance shows that it is possible to fabricate a nano-graphite-based switching device by the application of weak gate voltage bias.

Estimation of Self-Injection Length in Heterostructures of YBa2Cu3O7-δ Superconductor and La0.67Ca0.33MnO3 Manganite

2006 ◽  
Vol 111 ◽  
pp. 171-174
Author(s):  
S. Khatua ◽  
S. Wanchoo ◽  
T. Bannerjee ◽  
C.M. Thakar ◽  
S.K. Malik
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Length Scale ◽  
Deposition Technique ◽  
Spintronic Device ◽  
Growth Sequence ◽  
Ybco Layer ◽  
Spin Polarized

Epitaxial bilayers of YBa2Cu3O7-δ (YBCO) and La0.67Ca0.33MnO3 (LCMO) heterostructures have been prepared by pulsed laser deposition technique, the growth sequence being YBCO on LCMO. The length scale of the YBCO layer, which is rendered non-superconductor/insulator by selfinjection of the spin polarized quasiparticles, is estimated to be 850Å. This can be an important guiding parameter in spintronic device configuration/fabrication.

Spin polarized current through Cu-DNA modulated by a gate voltage

2013 ◽  
Vol 102 (7) ◽  
pp. 072410 ◽  
Author(s):  
D. W. Kang ◽  
X. P. Hao ◽  
X. Z. Li ◽  
L. B. Li ◽  
S. J. Xie
Keyword(s):  
Gate Voltage ◽  
Spin Polarized
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