Bandyopadhyay Supriyo
Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
J Nanosci Nanotechnol. 2007 Jan;7(1):168-80.
Champions of "spintronics" often claim that spin based signal processing devices will vastly increase speed and/or reduce power dissipation compared to traditional 'charge based' electronic devices. Yet, not a single spintronic device exists today that can lend credence to this claim. Here, I show that no spintronic device that clones conventional electronic devices, such as field effect transistors and bipolar junction transistors, is likely to reduce power dissipation significantly. For that to happen, spin-based devices must forsake the transistor paradigm of switching states by physical movement of charges, and instead, switch states by flipping spins of stationary charges. An embodiment of this approach is the "single spin logic" idea proposed more than 10 years ago. Here, I revisit that idea and present estimates of the switching speed and power dissipation. I show that the Single Spin Switch is far superior to the Spin Field Effect Transistor (or any of its clones) in terms of power dissipation. I also introduce the notion of "matrix element engineering" which will allow one to switch devices without raising and lowering energy barriers between logic states, thereby circumventing the kTln2 limit on energy dissipation. Finally, I briefly discuss single spin implementations of classical reversible (adiabatic) logic.
“自旋电子学”的支持者常常宣称，与传统的“基于电荷”的电子设备相比，基于自旋的信号处理设备将极大地提高速度和/或降低功耗。然而，如今还没有一个自旋电子设备能够支持这一说法。在此，我表明，没有一个克隆传统电子设备（如场效应晶体管和双极结型晶体管）的自旋电子设备可能会显著降低功耗。要实现这一点，基于自旋的设备必须摒弃通过电荷物理移动来切换状态的晶体管范式，转而通过翻转固定电荷的自旋来切换状态。这种方法的一个实例是10多年前提出的“单自旋逻辑”概念。在此，我重新审视这一概念，并给出开关速度和功耗的估计。我表明，单自旋开关在功耗方面远优于自旋场效应晶体管（或其任何克隆品）。我还引入了“矩阵元工程”的概念，它将使人们能够在不提高和降低逻辑状态之间的能垒的情况下切换设备，从而规避能量耗散的kTln2限制。最后，我简要讨论经典可逆（绝热）逻辑的单自旋实现方式。
