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- Huang, Yuqing, et al.
(författare)
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Tuneable Nonlinear Spin Response in a Nonmagnetic Semiconductor
- 2023
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Ingår i: Physical Review Applied. - : AMER PHYSICAL SOC. - 2331-7019. ; 19:6
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Tidskriftsartikel (refereegranskat)abstract
- Nonlinear effects and dynamics are found in a wide range of research fields. In magnetic materials, nonlinear spin dynamics enables ultrafast manipulation of spin, which promises high-speed nonvolatile information processing and storage for future spintronic applications. However, a nonlinear spin response is not yet demonstrated in a nonmagnetic material that lacks strong magnetic interactions. Dilute nitride III-V materials, e.g., (Ga, N)As, have the ability to amplify the conduction-electron-spin polarization by filtering out minority spins via spin-polarized defect states at room temperature. Here, by employing coupled rate equations, we theoretically demonstrate the emergence of a nonlinear spin response in such a defect-enabled room-temperature spin amplifier. Furthermore, we showcase the proposed spin nonlinearity in a (Ga, N)As-InAs quantum dot (QD) coupled all-semiconductor nanostructure, by measuring the higher-harmonic generation, which converts the modulation of excitation polarization into the second-, third-, and fourth-order harmonic oscillations of the QDs photoluminescence intensity and polarization. The observed spin nonlinearity originates from defect-mediated spin-dependent recombination, which can be conveniently tuned with an external magnetic field and can potentially operate at a speed exceeding 1 GHz. The demonstrated spin nonlinearity could pave the way for nonlinear spintronic and optospintronic device applications based on nonmagnetic semiconductors with simultaneously achievable high operation speed and nonlinear response.
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| 2. |
- Moosavi, S. R., et al.
(författare)
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End-to-end security scheme for mobility enabled healthcare Internet of Things
- 2016
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Ingår i: Future generations computer systems. - : Elsevier. - 0167-739X .- 1872-7115.
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Tidskriftsartikel (refereegranskat)abstract
- We propose an end-to-end security scheme for mobility enabled healthcare Internet of Things (IoT). The proposed scheme consists of (i) a secure and efficient end-user authentication and authorization architecture based on the certificate based DTLS handshake, (ii) secure end-to-end communication based on session resumption, and (iii) robust mobility based on interconnected smart gateways. The smart gateways act as an intermediate processing layer (called fog layer) between IoT devices and sensors (device layer) and cloud services (cloud layer). In our scheme, the fog layer facilitates ubiquitous mobility without requiring any reconfiguration at the device layer. The scheme is demonstrated by simulation and a full hardware/software prototype. Based on our analysis, our scheme has the most extensive set of security features in comparison to related approaches found in literature. Energy-performance evaluation results show that compared to existing approaches, our scheme reduces the communication overhead by 26% and the communication latency between smart gateways and end users by 16%. In addition, our scheme is approximately 97% faster than certificate based and 10% faster than symmetric key based DTLS. Compared to our scheme, certificate based DTLS consumes about 2.2 times more RAM and 2.9 times more ROM resources. On the other hand, the RAM and ROM requirements of our scheme are almost as low as in symmetric key-based DTLS. Analysis of our implementation revealed that the handover latency caused by mobility is low and the handover process does not incur any processing or communication overhead on the sensors.
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| 3. |
- Moosavi, S. R., et al.
(författare)
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Session resumption-based end-to-end security for healthcare internet-of-things
- 2015
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Ingår i: Proceedings - 15th IEEE International Conference on Computer and Information Technology, CIT 2015, 14th IEEE International Conference on Ubiquitous Computing and Communications, IUCC 2015, 13th IEEE International Conference on Dependable, Autonomic and Secure Computing, DASC 2015 and 13th IEEE International Conference on Pervasive Intelligence and Computing, PICom 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509001545 ; , s. 581-588
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Konferensbidrag (refereegranskat)abstract
- In this paper, a session resumption-based end-toend security scheme for healthcare Internet of things (IoT) is proposed. The proposed scheme is realized by employing certificatebased DTLS handshake between end-users and smart gateways as well as utilizing DTLS session resumption technique. Smart gateways enable the sensors to no longer need to authenticate and authorize remote end-users by handing over the necessary security context Session resumption technique enables end-users and medical sensors to directly communicate without the need for establishing the communication from the initial handshake. Session resumption technique has an abbreviated form of DTLS handshake and neither requires certificate-related nor public-key funtionalities. This alleviates some burden of medical sensors to no longer need to perform expensive operations. The energyperformance evaluations of the proposed scheme are evaluated by developing a remote patient monitoring prototype based on healthcare IoT. The energy-performance evaluation results show that our scheme is about 97% and 10% faster than certificatebased and symmetric key-based DTLS, respectively. Also, the certificate-based DTLS consumes about 2.2X more RAM and 2.9X more ROM resources required by our scheme. While, our scheme and symmetric key-based DTLS have almost similar RAM and ROM requirements. The security analysis reveals that the proposed scheme fulfills the requirements of end-to-end security and provides higher security level than related approaches found in the literature. Thus, the presented scheme is a wellsuited solution to provide end-to-end security for healthcare IoT.
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