The electron is responsible for charge and spin transport in conventional metals. In contrast, the existence of well-defined electronic excitations in the metallic state of high-temperature ...

The most direct way to measure the electronic excitation spectrum of a solid is angle-resolved photoemission spectroscopy (ARPES), which gives the energy- and momentum-dependent spectral function 11.

Scanning tunneling microscopy (STM) is an experimental technique based on the principles of quantum tunneling of electrons between two electrodes separated by a potential barrier, typically used for ...