Spin-½

About: Spin-½ is a research topic. Over the lifetime, 40423 publications have been published within this topic receiving 796639 citations.

Strongly anisotropic spin relaxation in graphene–transition metal dichalcogenide heterostructures at room temperature

Abstract: A large enhancement in the spin–orbit coupling of graphene has been predicted when interfacing it with semiconducting transition metal dichalcogenides. Signatures of such an enhancement have been reported, but the nature of the spin relaxation in these systems remains unknown. Here, we unambiguously demonstrate anisotropic spin dynamics in bilayer heterostructures comprising graphene and tungsten or molybdenum disulphide (WS2, MoS2). We observe that the spin lifetime varies over one order of magnitude depending on the spin orientation, being largest when the spins point out of the graphene plane. This indicates that the strong spin–valley coupling in the transition metal dichalcogenide is imprinted in the bilayer and felt by the propagating spins. These findings provide a rich platform to explore coupled spin–valley phenomena and offer novel spin manipulation strategies based on spin relaxation anisotropy in two-dimensional materials. Large spin–orbit coupling can be induced when graphene interfaces with semiconducting transition metal dichalcogenides, leading to strongly anisotropic spin dynamics. As a result, orientation-dependent spin relaxation is observed.

Electron transport in quantum dots

Abstract: 1 Interactions, Spins and the Kondo Effect in Quantum-Dot Systems.- 1 Introduction.- 2 Atom-Like Properties of Electrons Confined in a Quantum Dot.- 3 Tunable Spin States with Magnetic Field.- 4 Spin Blockade in Single Electron Tunneling.- 5 Energy Relaxation with and Without Spin-Flip.- 6 The Kondo Effect in Quantum Dots.- 7 Summary.- 2 Microwave Spectroscopy on Single and Coupled Quantum Dots.- 1 Introduction.- 2 Aspects of Fabrication.- 3 Measurement Techniques.- 4 Coherent Modes in Quantum Dots.- 5 Photon Assisted Tunneling in Quantum Dots.- 6 Dynamic Response of Single Quantum Dots.- 7 The On-Chip Spectrometer.- 8 Non-Linear Transmission-Lines for Probing Single Dots.- 9 Summary.- 3 Nano-Spintronics with Lateral Quantum Dots.- 1 Introduction.- 2 Theoretical Framework.- 3 Experimental Devices and Techniques.- 4 Spin-Polarized Injection and Detection.- 5 Coulomb and Spin Blockade Spectrum.- 6 The First Few Electrons.- 7 The ? = 2 Regime.- 8 The Spin Flip Regime.- 9 Negative Differential Resistance Achieved by Spin Blockade.- 10 Conclusions.- 4 Novel Phenomena in Small Individual and Coupled Quantum Dots.- 1 Introduction.- 2 Models of Single and Double Quantum Dot Systems.- 3 Non-Gaussian Distribution of Coulomb Blockade Peak Heights in Individual Quantum Dots: Porter-Thomas Distribution of Resonance Widths.- 4 Spin and Pairing Effects in Ultra-Small Dots.- 5 Coupling between Two Dots and Leads-Coherent Many-Body Kondo States.- 6 Other Ultra-Small Devices and Phenomena.- 5 Classical and Quantum Transport in Antidot Arrays.- 1 Introduction.- 2 Antidot Arrays.- 3 Early Experiments and Pinball Model.- 4 Chaotic Dynamics in Antidot Lattices.- 5 Quantum Effects in Antidot Arrays.- 6 Random Antidot Arrays.- 7 Finite Antidot Lattices.- 8 InAs Based Arrays.- 9 Other Experiments.- 6 On the Influence of Resonant States on Ballistic Transport in Open Quantum Dots: Spectroscopy and Tunneling in the Presence of Multiple Conducting Channels.- 1 Introduction.- 2 Some Comments about Semiclassical Theories and their Underlying Assumptions.- 3 The Method of Calculation Used Primarily in this Work: A Fully Quantum Mechanical Treatment.- 4 Conductance Resonances in Open Dots.- 5 The Correspondence Between Conductance Resonances in Open Dots and Closed Dot Eigenstates.- 6 The Effect of Finite Temperature and Ensemble Averaging.- 7 Direct Comparisons of Theory with Experiment.- 8 An Alternate Semiclassical Interpretation of Transport in Open Quantum Dots: Dynamical Tunneling.- 9 Summary.- 10 Acknowledgment.- 7 A Review of Fractal Conductance Fluctuations in Ballistic Semiconductor Devices.- 1 Introduction.- 2 The Semiconductor Sinai Billiard: Can Chaos be Controlled with the "Flick of a Switch?".- 3 The Experimental Observation of Exact Self-Affinity.- 4 The Interpretation of Exact Self-Affinity.- 5 The Observation of Statistical Self-Affinity.- 6 The Classical to Quantum Transition: How do Fractals "Disappear?".- 7 The Role Played by the Billiard Walls.- 8 Conclusions.- 8 Electron Ratchets-Nonlinear Transport in Semiconductor Dot and Antidot Structures.- 1 Introduction.- 2 Non-Linear Rectification in the Quantum Regime.- 3 Nonlinear Transport in Antidot Structures.- 4 Outlook.- 9 Single-Photon Detection with Quantum Dots in the Far-Infrared/Submillimeter-Wave Range.- 1 Introduction.- 2 Fundamental Characteristics of the SET.- 3 Designing a Single-Photon Detector.- 4 Detection in Magnetic Fields.- 5 Detection in the Absence of Magnetic Field.- 6 Detector Performance.- 7 Conclusion.- 10 Quantum-Dot Cellular Automata.- 1 Introduction.- 2 The Quantum-Dot Cellular Automata Paradigm.- 3 Experimental Demonstrations of QCA: Metal-Dot Systems.- 4 Molecular QCA.- 5 Architecture for QCA.- 6 Magnetic QCA.- 11 Carbon Nanotubes for Nanoscale Spin-Electronics.- 1 Introduction.- 2 Spin Transport in Carbon Nanotubes.- 3 Conclusions.

Quantum spin liquid in the spin-1/2 triangular antiferromagnet EtMe$_{3}$Sb[Pd(dmit)$_{2}$]$_{2}$

Abstract: The family of layered organic salts $X{[\\mathrm{Pd}{(\\text{dmit})}_{2}]}_{2}$ are Mott insulators and form scalene-triangular spin-$1∕2$ systems. Among them, $\\mathrm{Et}{\\mathrm{Me}}_{3}\\mathrm{Sb}{[\\mathrm{Pd}{(\\text{dmit})}_{2}]}_{2}$ has a nearly regular-triangular lattice. We have investigated the spin state of this salt by $^{13}\\mathrm{C}\\text{\\ensuremath{-}}\\mathrm{NMR}$ and static susceptibility measurements. The temperature dependence of the susceptibility is described as that of a regular-triangular antiferromagnetic spin-$1∕2$ system with an exchange interaction $J=220\\ensuremath{-}250\\phantom{\\rule{0.3em}{0ex}}\\mathrm{K}$. The $^{13}\\mathrm{C}\\text{\\ensuremath{-}}\\mathrm{NMR}$ measurements reveal that there is no indication of either spin ordering/freezing or an appreciable spin gap down to $1.37\\phantom{\\rule{0.3em}{0ex}}\\mathrm{K}$, which is lower than 1% of $J$. This result strongly suggests that this system is in the quantum spin-liquid state with no appreciable spin gap, which has been long sought after.

Strong Field Interactions between a Nanomagnet and a Photonic Cavity

Abstract: We analyze the interaction of a nanomagnet (ferromagnetic) with a single photonic mode of a cavity in a fully quantum-mechanical treatment and find that exceptionally large quantum-coherent magnet-photon coupling can be achieved. Coupling terms in excess of several THz are predicted to be achievable in a spherical cavity of approximately 1 mm radius with a nanomagnet of approximately 100 nm radius and ferromagnetic resonance frequency of approximately 200 GHz. Eigenstates of the magnet-photon system correspond to entangled states of spin orientation and photon number, in which over 10{5} values of each quantum number are represented; conversely, initial (coherent) states of definite spin and photon number evolve dynamically to produce large oscillations in the microwave power (and nanomagnet spin orientation), and are characterized by exceptionally long dephasing times.

Spin-orbit excitation energies, anisotropic exchange, and magnetic phases of honeycomb RuCl3

Abstract: Using quantum chemistry calculations we shed fresh light on the electronic structure and magnetic properties of RuCl3, a proposed realization of the honeycomb Kitaev spin model. It is found that the nearest-neighbor Kitaev exchange K is weaker than in 5d5 Ir oxides but still larger than other effective spin couplings. The electronic-structure computations also indicate a ferromagnetic K in the halide, which is supported by a detailed analysis of the field-dependent magnetization. From exact-diagonalization calculations for extended Kitaev-Heisenberg Hamiltonians we additionally find that a transition from zigzag order to a spin-liquid ground state can be induced in RuCl3 with external magnetic field.