scholarly journals Non-monotonic variation of the Kramers point band gap with increasing magnetic doping in BiTeI

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. M. Shikin ◽  
A. A. Rybkina ◽  
D. A. Estyunin ◽  
I. I. Klimovskikh ◽  
A. G. Rybkin ◽  
...  
Keyword(s):  
Doping Level ◽  
Quantum Interference ◽  
Energy Gap ◽  
Magnetic Ordering ◽  
Magnetic Impurities ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Magnetic Elements ◽  
Gap Opening ◽  
Type Semiconductor ◽  
Ferromagnetic Ordering

AbstractPolar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.

scholarly journals Non-monotonic variation of the Kramers point band gap with increasing magnetic doping in BiTeI

2021 ◽  
Author(s):  
A. M. Shikin ◽  
A. A. Rybkina ◽  
D. A. Estyunin ◽  
I. I. Klimovskikh ◽  
A. G. Rybkin ◽  
...  
Keyword(s):  
Doping Level ◽  
Quantum Interference ◽  
Energy Gap ◽  
Magnetic Ordering ◽  
Magnetic Impurities ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Magnetic Elements ◽  
Gap Opening ◽  
Type Semiconductor ◽  
Ferromagnetic Ordering

Abstract Polar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.

scholarly journals Band-selective gap opening by a C4-symmetric order in a proximity-coupled heterostructure Sr2VO3FeAs

2021 ◽  
Vol 118 (47) ◽  
pp. e2105190118
Author(s):  
Sunghun Kim ◽  
Jong Mok Ok ◽  
Hanbit Oh ◽  
Chang Il Kwon ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Energy Gap ◽  
Strongly Correlated ◽  
Strongly Correlated Electron ◽  
Fermi Surfaces ◽  
Correlated Electron Systems ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Broken Symmetries ◽  
Correlated Electron ◽  
Gap Opening

Complex electronic phases in strongly correlated electron systems are manifested by broken symmetries in the low-energy electronic states. Some mysterious phases, however, exhibit intriguing energy gap opening without an apparent signature of symmetry breaking (e.g., high-TC cuprates and heavy fermion superconductors). Here, we report an unconventional gap opening in a heterostructured, iron-based superconductor Sr2VO3FeAs across a phase transition at T0 ∼150 K. Using angle-resolved photoemission spectroscopy, we identify that a fully isotropic gap opens selectively on one of the Fermi surfaces with finite warping along the interlayer direction. This band selectivity is incompatible with conventional gap opening mechanisms associated with symmetry breaking. These findings, together with the unusual field-dependent magnetoresistance, suggest that the Kondo-type proximity coupling of itinerant Fe electrons to localized V spin plays a role in stabilizing the exotic phase, which may serve as a distinct precursor state for unconventional superconductivity.

Local Energy Gap Opening Induced by Hemin Dimerization in Aqueous Solution

2015 ◽  
Vol 119 (7) ◽  
pp. 3058-3062 ◽  
Author(s):  
Ronny Golnak ◽  
Jie Xiao ◽  
Kaan Atak ◽  
Munirah Khan ◽  
Edlira Suljoti ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Energy Gap ◽  
Local Energy ◽  
Gap Opening

Energy gap opening by crossing drop cast single-layer graphene nanoribbons

2018 ◽  
Vol 29 (31) ◽  
pp. 315705 ◽  
Author(s):  
Toyo Kazu Yamada ◽  
Hideto Fukuda ◽  
Taizo Fujiwara ◽  
Polin Liu ◽  
Kohji Nakamura ◽  
...  
Keyword(s):  
Energy Gap ◽  
Graphene Nanoribbons ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Gap Opening

scholarly journals Análisis cristalográfico, morfológico, eléctrico, óptico y magnético del nuevo material Dy2BiFeO6

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Jairo Roa-Rojas
Keyword(s):  
Dielectric Constant ◽  
Energy Gap ◽  
Magnetic Hysteresis ◽  
Magnetic Ordering ◽  
Relative Dielectric Constant ◽  
Double Perovskite ◽  
Crystallographic Analysis ◽  
Weiss Temperature ◽  
Constant E ◽  
Diffraction Patterns

We report structural analysis, surface morphology, magnetic ordering, dielectric response, optical feature and the electronic structure of the Dy2BiFeO6 novel complex perovskite. The samples were produced by the standard solid-state reaction recipe. Crystallographic analysis was performed by Rietveld refinement of experimental X-ray diffraction patterns. Results show that this material crystallizes in a perovskite with orthorhombic structure, which corresponds to the Pnma (#62) space group. From the Curie-Weiss fitting on the curve of susceptibility as a function of temperature we establish that the ordering corresponds to a paramagnetic-antiferromagnetic transition, with a Weiss temperature q=-18,5 K, which is compatible with the behavior of the inverse of susceptibility as a function of temperature, and a Néel temperatura TN=50,8 K. The Curie constant allowed for us to obtain an effective magnetic moment of 15,7 mB. The result of magnetization as a function of the applied field, measured at T=50 K, shows a magnetic hysteresis behavior that corroborate the magnetic ordering present for this temperature value. Measurements of the dielectric constant as a function of applied frequencies at room temperature give as a result a high relative dielectric constant (e=780). The reflectance curve as a function of the wavelength reveals the typical behavior of a double perovskite-like material and permits to obtain the energy gap 2,74 eV, which is characteristic of a semiconductor material.

scholarly journals Analysis of energy gap opening in graphene oxide

2014 ◽  
Vol 526 ◽  
pp. 012003 ◽  
Author(s):  
Mark Lundie ◽  
Željko Šljivančanin ◽  
Stanko Tomić
Keyword(s):  
Graphene Oxide ◽  
Energy Gap ◽  
Gap Opening

scholarly journals Evidence for a vestigial nematic state in the cuprate pseudogap phase

2019 ◽  
Vol 116 (27) ◽  
pp. 13249-13254 ◽  
Author(s):  
Sourin Mukhopadhyay ◽  
Rahul Sharma ◽  
Chung Koo Kim ◽  
Stephen D. Edkins ◽  
Mohammad H. Hamidian ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Energy Gap ◽  
Density Wave ◽  
Broken Symmetry ◽  
Hole Doping ◽  
Thermal Transitions ◽  
Electronic Density ◽  
Pseudogap Phase ◽  
Nematic State ◽  
Gap Opening

The CuO2 antiferromagnetic insulator is transformed by hole-doping into an exotic quantum fluid usually referred to as the pseudogap (PG) phase. Its defining characteristic is a strong suppression of the electronic density-of-states D(E) for energies |E| < Δ*, where Δ* is the PG energy. Unanticipated broken-symmetry phases have been detected by a wide variety of techniques in the PG regime, most significantly a finite-Q density-wave (DW) state and a Q = 0 nematic (NE) state. Sublattice-phase-resolved imaging of electronic structure allows the doping and energy dependence of these distinct broken-symmetry states to be visualized simultaneously. Using this approach, we show that even though their reported ordering temperatures TDW and TNE are unrelated to each other, both the DW and NE states always exhibit their maximum spectral intensity at the same energy, and using independent measurements that this is the PG energy Δ*. Moreover, no new energy-gap opening coincides with the appearance of the DW state (which should theoretically open an energy gap on the Fermi surface), while the observed PG opening coincides with the appearance of the NE state (which should theoretically be incapable of opening a Fermi-surface gap). We demonstrate how this perplexing phenomenology of thermal transitions and energy-gap opening at the breaking of two highly distinct symmetries may be understood as the natural consequence of a vestigial nematic state within the pseudogap phase of Bi2Sr2CaCu2O8.

Magnetic properties of cobalt single layer added on graphene: A density functional theory study

2015 ◽  
Vol 29 (02) ◽  
pp. 1450262 ◽  
Author(s):  
M. Afshar ◽  
H. Doosti
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Single Layer ◽  
Magnetic Ordering ◽  
Polarization Degree ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Half Metallic ◽  
Cobalt Layer ◽  
Ferromagnetic Ordering

In this paper, we have demonstrated magnetic ordering of single cobalt layer added on graphene using relativistic density functional theory at the level of generalized gradient approximation. We have shown that the single Co layer added on graphene show ferromagnetic ordering with perpendicular alignment to the graphene sheet. In the presence of spin-orbit coupling, a spin-polarization degree of about 92% was found for this quasi-two-dimensional magnetic system where it is shown a nearly half-metallic feature.

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