铜氧化物高温超导体电子态物理性质的研究

当温度大于Tc，普通的低温超导体的正常态是费密液体。然而铜氧化物高温超导体的正常态显示一系列与费密液体行为不相符的反常特性。尽管正常态显示一系列反常物理性质，但是令人进退两难的是铜氧化物高温超导体的超导态的物理性质却不反常，而且也是可以由标准的BCS-形式论来描述，虽然形成库伯对的超导机理不是普通的电-声子机制。特别是实验上也指出铜氧化物高温超导体中的电子费密面服从Luttinger定理。我们在动能驱动的超导电性机理基础上建立了一个电荷自由度与自旋自由度完全重新组合的理论，并在此基础上获得的电子费密面满足Luttinger定理。我们也说明了在超导态时的低能激发可以由BCS-形式论来描述，虽然配对机制是通过动能通过交换自旋元激发而产生相互吸引作用。在这个理框架下，我们研究铜氧化物高温超导体的电子态及相关的物理性质，从而为铜氧化物高温超导体中出现的这些物理现象提供一个整体的微观物理说明。

At the temperature above Tc, the electron in conventional superconductors is in the Fermi-liquid state, which is generally referred to as a normal-state. However, the normal-state of cuprate superconductors is not normal at all, since the normal-state exhibits a number of the anomalous properties in the sense that they do not fit in with the Fermi liquid theory. In particular, one of the most striking dilemmas is that the superconducting coherence of the low-energy quasiparticle excitations in cuprate superconductors is described by the BCS formalism, although the normal-state is undoubtedly not the Fermi-liquid on which the conventional electron-phonon theory is based. Moreover, the underlying electron Fermi surface satisfies Luttinger's theorem. After intensive investigations over more than two decades, a large body of data available from a wide variety of measurement techniques have introduced important constraints on the microscopic model and SC theory. Within the kinetic-energy driven superconducting mechanism, a full charge-spin recombination scheme is developed, and then is employed to study the electronic structure of cuprate superconductors and the related electronic properties.