1. S. E. Thompson EEL 6935 1 Logic Devices Field Effect Devices –Si MOSFET –CNT-FET Coulomb Blockade Devices –Single Electron Devices Spintronics Resonant Tunneling Diodes Quantum cellular Automata Molecular Electronics Based on charge Non-charge based

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8. Spintronics 8 Spintronics: (a neologism for "spin-based electronics"), also known as magnetoelectronics, is an emerging technology which exploits the quantum spin states of electrons as well as making use of their charge state. The electron spin itself is manifested as a two state magnetic energy system. In order to make a spintronic device, the primary requirement is to have a system that can generate a current of spin polarized electrons, and a system that is sensitive to the spin polarization of the electrons. Most devices also have a unit in between that changes the current of electrons depending on the spin states.

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15. S. E. Thompson EEL 6935 15 How Spintronical Logic Works Interrelation between spin polarization and electronic transport Source and drain supposed to be ferromagnets S/D identical magnetization direction Channel semiconductor / highly mobile 2D gas No applied VG, spin polarization remains unchanged (on) VG applied (Electric field), experience magnetic field which rotates the spin. –High R (off)

16. S. E. Thompson EEL 6935 16Spintronics Concept based on 3 effects –(1) electrons injected into active region of transisotr need to show a high degree of spin polarization –There must be a control signal (electric, Magnetic, optical which makes it possibel to tune the spin polarization –Spin polarization must be sustained during distance of active region (long coherence time required).

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18. S. E. Thompson EEL 6935 18 Spintronics: What Has Been Demonstrated GaAs coherence for several 100ns and transports ~ 100um Coherence can be maintained across heterojunctions with GaN Generation of an efficient electron injection with a high degree of spin polarization at room temperature difficult –Best value spin polarization fo 2 and 13% at room temperature. –Fe into GaAs