GSTDTAP

浏览/检索结果: 共75条,第1-10条 帮助

已选(0)清除 条数/页:   排序方式:
Non-volatile electric control of spin-charge conversion in a SrTiO3 Rashba system 期刊论文
NATURE, 2020, 580 (7804) : 483-+
作者:  Collombet, Samuel;  Ranisavljevic, Noemie;  Nagano, Takashi;  Varnai, Csilla;  Shisode, Tarak;  Leung, Wing;  Piolot, Tristan;  Galupa, Rafael;  Borensztein, Maud;  Servant, Nicolas;  Fraser, Peter;  Ancelin, Katia;  Heard, Edith
收藏  |  浏览/下载:15/0  |  提交时间:2020/07/03

The polarization direction of a ferroelectric-like state can be used to control the conversion of spin currents into charge currents at the surface of strontium titanate, a non-magnetic oxide.


After 50 years of development, the technology of today'  s electronics is approaching its physical limits, with feature sizes smaller than 10 nanometres. It is also becoming clear that the ever-increasing power consumption of information and communication systems(1) needs to be contained. These two factors require the introduction of non-traditional materials and state variables. As recently highlighted(2), the remanence associated with collective switching in ferroic systems is an appealing way to reduce power consumption. A promising approach is spintronics, which relies on ferromagnets to provide non-volatility and to generate and detect spin currents(3). However, magnetization reversal by spin transfer torques(4) is a power-consuming process. This is driving research on multiferroics to achieve low-power electric-field control of magnetization(5), but practical materials are scarce and magnetoelectric switching remains difficult to control. Here we demonstrate an alternative strategy to achieve low-power spin detection, in a non-magnetic system. We harness the electric-field-induced ferroelectric-like state of strontium titanate (SrTiO3)(6-9) to manipulate the spin-orbit properties(10) of a two-dimensional electron gas(11), and efficiently convert spin currents into positive or negative charge currents, depending on the polarization direction. This non-volatile effect opens the way to the electric-field control of spin currents and to ultralow-power spintronics, in which non-volatility would be provided by ferroelectricity rather than by ferromagnetism.


  
Digital transformation and localizing the Sustainable Development Goals (SDGs) 期刊论文
ECOLOGICAL ECONOMICS, 2020, 169
作者:  ElMassah, Suzanna;  Mohieldin, Mahmoud
收藏  |  浏览/下载:17/0  |  提交时间:2020/07/02
Sustainable Development Goals  Localization  Digital transformation  Big data  e-government  Information technology  Regional development  Virtual decentralization  
Universal quantum logic in hot silicon qubits 期刊论文
NATURE, 2020, 580 (7803) : 355-+
作者:  Li, Jia;  Yang, Xiangdong;  Liu, Yang;  Huang, Bolong;  Wu, Ruixia;  Zhang, Zhengwei;  Zhao, Bei;  Ma, Huifang;  Dang, Weiqi;  Wei, Zheng;  Wang, Kai;  Lin, Zhaoyang;  Yan, Xingxu;  Sun, Mingzi;  Li, Bo;  Pan, Xiaoqing;  Luo, Jun;  Zhang, Guangyu;  Liu, Yuan;  Huang, Yu;  Duan, Xidong;  Duan, Xiangfeng
收藏  |  浏览/下载:41/0  |  提交时间:2020/07/03

Quantum computation requires many qubits that can be coherently controlled and coupled to each other(1). Qubits that are defined using lithographic techniques have been suggested to enable the development of scalable quantum systems because they can be implemented using semiconductor fabrication technology(2-5). However, leading solid-state approaches function only at temperatures below 100 millikelvin, where cooling power is extremely limited, and this severely affects the prospects of practical quantum computation. Recent studies of electron spins in silicon have made progress towards a platform that can be operated at higher temperatures by demonstrating long spin lifetimes(6), gate-based spin readout(7) and coherent single-spin control(8). However, a high-temperature two-qubit logic gate has not yet been demonstrated. Here we show that silicon quantum dots can have sufficient thermal robustness to enable the execution of a universal gate set at temperatures greater than one kelvin. We obtain single-qubit control via electron spin resonance and readout using Pauli spin blockade. In addition, we show individual coherent control of two qubits and measure single-qubit fidelities of up to 99.3 per cent. We demonstrate the tunability of the exchange interaction between the two spins from 0.5 to 18 megahertz and use it to execute coherent two-qubit controlled rotations. The demonstration of '  hot'  and universal quantum logic in a semiconductor platform paves the way for quantum integrated circuits that host both the quantum hardware and its control circuitry on the same chip, providing a scalable approach towards practical quantum information processing.


  
Direct-bandgap emission from hexagonal Ge and SiGe alloys 期刊论文
NATURE, 2020, 580 (7802) : 205-+
作者:  Meiners, Thorsten;  Frolov, Timofey;  Rudd, Robert E.;  Dehm, Gerhard;  Liebscher, Christian H.
收藏  |  浏览/下载:28/0  |  提交时间:2020/07/03

Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si), germanium (Ge) and SiGe alloys are all indirect-bandgap semiconductors that cannot emit light efficiently. The goal(1) of achieving efficient light emission from group-IV materials in silicon technology has been elusive for decades(2-6). Here we demonstrate efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys. We measure a sub-nanosecond, temperature-insensitive radiative recombination lifetime and observe an emission yield similar to that of direct-bandgap group-III-V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information-processing technologies.


A hexagonal (rather than cubic) alloy of silicon and germanium that has a direct (rather than indirect) bandgap emits light efficiently across a range of wavelengths, enabling electronic and optoelectronic functionalities to be combined on a single chip.


  
Current-driven magnetic domain-wall logic 期刊论文
NATURE, 2020, 579 (7798) : 214-+
作者:  Culp, Elizabeth J.;  Waglechner, Nicholas;  Wang, Wenliang;  Fiebig-Comyn, Aline A.;  Hsu, Yen-Pang;  Koteva, Kalinka;  Sychantha, David;  Coombes, Brian K.;  Van Nieuwenhze, Michael S.;  Brun, Yves, V;  Wright, Gerard D.
收藏  |  浏览/下载:31/0  |  提交时间:2020/07/03

Spin-based logic architectures provide nonvolatile data retention, near-zero leakage, and scalability, extending the technology roadmap beyond complementary metal-oxide-semiconductor logic(1-13). Architectures based on magnetic domain walls take advantage of the fast motion, high density, non-volatility and flexible design of domain walls to process and store information(1,3,14-16). Such schemes, however, rely on domain-wall manipulation and clocking using an external magnetic field, which limits their implementation in dense, large-scale chips. Here we demonstrate a method for performing all-electric logic operations and cascading using domain-wall racetracks. We exploit the chiral coupling between neighbouring magnetic domains induced by the interfacial Dzyaloshinskii-Moriya interaction(17-20), which promotes non-collinear spin alignment, to realize a domain-wall inverter, the essential basic building block in all implementations of Boolean logic. We then fabricate reconfigurable NAND and NOR logic gates, and perform operations with current-induced domain-wall motion. Finally, we cascade several NAND gates to build XOR and full adder gates, demonstrating electrical control of magnetic data and device interconnection in logic circuits. Our work provides a viable platform for scalable all-electric magnetic logic, paving the way for memory-in-logic applications.


  
Data center growth in the United States: decoupling the demand for services from electricity use 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2018, 13 (12)
作者:  Shehabi, Arman;  Smith, Sarah J.;  Masanet, Eric;  Koomey, Jonathan
收藏  |  浏览/下载:8/0  |  提交时间:2019/04/09
information and communication technology (ICT)  energy efficiency  energy demand modeling  data centers  
Smart Earth: A meta-review and implications for environmental governance 期刊论文
GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS, 2018, 52: 201-211
作者:  Bakker, Karen;  Ritts, Max
收藏  |  浏览/下载:9/0  |  提交时间:2019/04/09
Eco-informatics  Environmental governance  Smart earth  Ecology  ICT  IoT  Information and communications technology  Internet of things  Sensors  Digital  
Why are rented dwellings less energy-efficient? Evidence from a representative sample of the US housing stock 期刊论文
ENERGY POLICY, 2018, 118: 149-159
作者:  Souza, M. N. M.
收藏  |  浏览/下载:4/0  |  提交时间:2019/04/09
Energy efficiency  Technology adoption  Asymmetric information  Housing markets  Landlord-tenant problem  
Symmetry 2017- The First International Conference on Symmetry 会议
Barcelona, Spain, 会议类型: Conference;Exhibition;Seminar, 2017