arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1609.08451cond-mat.supr-con
收藏

超导电子的动量和迈斯纳效应的解释

Momentum of superconducting electrons and the explanation of the Meissner effect

J. E. Hirsch

摘要:

动量和能量守恒是物理学的基本原理,有效的物理理论必须满足。在磁场存在的超导相和正常相之间的可逆变换中,超导电流的机械动量必须转移到作为整体的物体,反之亦然,超导电流的动能停留在电子自由度中,并且在该过程中没有能量耗散,也没有熵产生。我们认为,一般的理由,解释这些过程是必要的,电磁场介导的电子和身体之间的动量转移作为一个整体,这需要当正常和超导相之间的相边界被移位,流动和逆流的电荷发生在垂直于相边界的方向。这种流动和逆流不会发生根据传统的BCS-伦敦理论的超导性,因此,我们认为,在BCS-伦敦理论的迈斯纳过渡是一个“禁止过渡”。此外,要解释相变的原因,必须使其与实验观测相一致:(i)相界附近超导电子的波函数$and$电荷分布延伸到正常相;(ii)正常态的载流子具有空穴性质。传统的超导理论不具备这些物理要素,空穴超导理论具备这些物理要素。

英文摘要:

Momentum and energy conservation are fundamental tenets of physics, that valid physical theories have to satisfy. In the reversible transformation between superconducting and normal phases in the presence of a magnetic field, the mechanical momentum of the supercurrent has to be transferred to the body as a whole and vice versa, the kinetic energy of the supercurrent stays in the electronic degrees of freedom, and no energy is dissipated nor entropy is generated in the process. We argue on general grounds that to explain these processes it is necessary that the electromagnetic field mediates the transfer of momentum between electrons and the body as a whole, and this requires that when the phase boundary between normal and superconducting phases is displaced, a flow and counterflow of charge occurs in direction perpendicular to the phase boundary. This flow and counterflow does not occur according to the conventional BCS-London theory of superconductivity, therefore we argue that within BCS-London theory the Meissner transition is a `forbidden transition'. Furthermore, to explain the phase transformation in a way that is consistent with the experimental observations requires that (i) the wavefunction $and$ charge distribution of superconducting electrons near the phase boundary extend into the normal phase, and (ii) that the charge carriers in the normal state have hole-like character. The conventional theory of superconductivity does not have these physical elements, the theory of hole superconductivity does.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑