arXiv subjects

Dong Pan

Publications and source records attributed to Dong Pan.

62 records · Page 4Linked to original sources

arXiv2018

Gate defined quantum dot realized in a single crystalline InSb nanosheet

Single crystalline InSb nanosheet is an emerging planar semiconductor material with potential applications in electronics, infrared optoelectronics, spintronics and topological quantum computing. Here we report on realization of a quantum dot device from a single crystalline InSb nanosheet grown by molecular-beam epitaxy. The device is fabricated from the nanosheet on a Si/SiO2 substrate and the quantum dot confinement is achieved by top gate technique. Transport measurements show a series of Coulomb diamonds, demonstrating that the quantum dot is well defined and highly tunable. Tunable, gate-defined, planar InSb quantum dots offer a renewed platform for developing semiconductor-based quantum computation technology.

cond-mat.mes-hall↗

arXiv2018

Anisotropic Pauli spin-blockade effect and spin-orbit interaction field in an InAs nanowire double quantum dot

We report on experimental detection of the spin-orbit interaction field in an InAs nanowire double quantum dot device. In the spin blockade regime, leakage current through the double quantum dot is measured and is used to extract the effects of spin-orbit interaction and hyperfine interaction on spin state mixing. At finite magnetic fields, the leakage current arising from the hyperfine interaction is suppressed and the spin-orbit interaction dominates spin state mixing. We observe dependence of the leakage current on the applied magnetic field direction and determine the direction of the spin-orbit interaction field. We show that the spin-orbit field lies in a direction perpendicular to the nanowire axis but with a pronounced off-substrate-plane angle. It is for the first time that such an off-substrate-plane spin-orbit field in an InAs nanowire has been detected. The results are expected to have an important implication in employing InAs nanowires to construct spin-orbit qubits and topological quantum devices.

cond-mat.mes-hall↗

arXiv2017

Quantum random number generator based on quantum tunneling effect

In this paper, we proposed an experimental implementation of quantum random number generator(QRNG) with inherent randomness of quantum tunneling effect of electrons. We exploited InGaAs/InP diodes, whose valance band and conduction band shared a quasi-constant energy barrier. We applied a bias voltage on the InGaAs/InP avalanche diode, which made the diode works under Geiger mode, and triggered the tunneling events with a periodic pulse. Finally, after data collection and post-processing, our quantum random number generation rate reached 8Mb/s, and final data was verified by NIST test and Diehard test. Our experiment is characterized as an innovative low-cost, photonic source free, integratable or even chip-achievable method in quantum random number generation.

quant-ph↗

arXiv2017

Coherent transport in a linear triple quantum dot made from a pure-phase InAs nanowire

A highly tunable linear triple quantum dot (TQD) device is realized in a single-crystalline pure-phase InAs nanowire using a local finger gate technique. The electrical measurements show that the charge stability diagram of the TQD can be represented by three kinds of current lines of different slopes and a simulation performed based on a capacitance matrix model confirms the experiment. We show that each current line observable in the charge stability diagram is associated with a case where a QD is on resonance with the Fermi level of the source and drain reservoirs. At a triple point where two current lines of different slopes move together but show anti-crossing, two QDs are on resonance with the Fermi level of the reservoirs. We demonstrate that an energetically degenerated quadruple point, at which all three QDs are on resonance with the Fermi level of the reservoirs, can be built by moving two separated triple points together via sophistically tuning of energy levels in the three QDs. We also demonstrate the achievement of direct coherent electron transfer between the two remote QDs in the TQD, realizing a long-distance coherent quantum bus operation. Such a long-distance coherent coupling could be used to investigate coherent spin teleportation and super-exchange effects and to construct a spin qubit with an improved long coherent time and with spin state detection solely by sensing the charge states.

cond-mat.mes-hall↗

arXiv2016

Measurements of the spin-orbit interaction and Landé g factor in a pure-phase InAs nanowire double quantum dot in the Pauli spin-blockade regime

We demonstrate direct measurements of the spin-orbit interaction and Landé g factors in a semiconductor nanowire double quantum dot. The device is made from a single-crystal pure-phase InAs nanowire on top of an array of finger gates on a Si/SiO$_2$ substrate and the measurements are performed in the Pauli spin-blockade regime. It is found that the double quantum dot exhibits a large singlet-triplet energy splitting of $Δ_{ST}\sim 2.3$ meV, a strong spin-orbit interaction of $Δ_{SO}\sim 140$ $μ$eV, and a large and strongly level-dependent Landé g factor of $\sim 12.5$. These results imply that single-crystal pure-phase InAs nanowires are desired semiconductor nanostructures for applications in quantum information technologies.

cond-mat.mes-hall↗

arXiv2015

Free-Standing Two-Dimensional Single-Crystalline InSb Nanosheets

Growth of high-quality single-crystalline InSb layers remains challenging in material science. Such layered InSb materials are highly desired for searching for and manipulation of Majorana fermions in solid state, a fundamental research task in physics today, and for development of novel high-speed nanoelectronic and infrared optoelectronic devices. Here we report on a new route towards growth of single-crystalline, layered InSb materials. We demonstrate the successful growth of free-standing, two-dimensional InSb nanosheets on one-dimensional InAs nanowires by molecular-beam epitaxy. The grown InSb nanosheets are pure zinc-blende single crystals. The length and width of the InSb nanosheets are up to several micrometers and the thickness is down to ~10 nm. The InSb nanosheets show a clear ambipolar behavior and a high electron mobility. Our work will open up new technology routes towards the development of InSb-based devices for applications in nanoelectronics, optoelectronics and quantum electronics, and for study of fundamental physical phenomena.

cond-mat.mtrl-sci↗

arXiv2013

Tailoring Magnetism of Perpendicularly Magnetized MnxGa Epitaxial Films on GaAs for Practical Applications

MnxGa films with high perpendicular anisotropy, coercivity and energy product have great application potential in ultrahigh-density perpendicular recording, permanent magnets, spin-transfer-torque memory and oscillators, magneto-resistance sensors and ferromagnetic metal/semiconductor heterostructure devices. Here we present a comprehensive diagram of effective magnetism-tailoring of perpendicularly magnetized MnxGa films grown on III-V semiconductor GaAs by using molecular-beam epitaxy for the first time, by systematically investigating the wide-range composition and detailed post-growth annealing effects. We show that the (001)-orientated MnxGa films with L10 or D022 ordering could be crystallized on GaAs in a very wide composition range from x=0.76 to 2.6. L10-ordered MnxGa films show robust magnetization, high remanent ratio, giant perpendicular anisotropy, high intrinsic and extrinsic coercivity, and large energy product, which make this kind of material favorable for perpendicular magnetic recording, high-performance spintronic devices and permanent magnet applications. In contrast, D022-ordered films exhibit lower perpendicular anisotropy and weaker magnetism. Post-growth annealing MnxGa films studies reveal high thermal-stability up to 450 oC, and effective tailoring of magnetic properties can be realized by prolonging annealing at 450 oC. These results would be helpful for understanding this kind of material and designing new spintronic devices for specific practical applications.

cond-mat.mtrl-sci↗

arXiv2012

Multifunctional L10-Mn1.5Ga films with ultrahigh coercivity, giant perpendicular magnetocrystalline anisotropy and large magnetic energy product

We present the fascinating magnetic properties in homogenous noble-metal-free and rare-earth-free L10-Mn1.5Ga epitaxial films on GaAs (001), including ultrahigh perpendicular coercivity remarkably tunable from 8.1 to 42.8 kOe, giant perpendicular magnetocrystalline anisotropy with a maximum of 22.9 Merg/cc, easily controllable magnetization from 27.3 to 270.5 emu/cc, excellent squareness exceeding 0.94 and large magnetic energy product up to 2.6 MGOe. These magnificent room-temperature magnetic characteristics make our L10-Mn1.5Ga films multifunctional as outstanding and cost-effective alternative for not only perpendicular magnetic recording bits with areal density over 30 Tb inch-2 and thermal stability over 60 years, but variety of novel devices with high magnetic-noise immunity and thermal stability like spin-torque MRAMs and oscillators pillars below 5 nm in dimension, and giant magnetoresistance sensors able to measure high fileds up to 42 kOe . Moreover, this kind of materials can also be expected as permanent magnets for replacing the expensive rare-earth magnets widely used today.

cond-mat.mtrl-sci↗