The charge-density-wave order in CuTe.
Electrons in classical metals such as Al and Cu are massive and known to move at the characteristic speed of Fermi velocity. In quantum matters, electrons theoretically turn out to be massless and the Fermi velocity is as if the virtual speed of light. It has been understood that electronic orders in metals can localize electrons and readily make these carriers heavier and slower, with charge density waves as a ubiquitous order of this kind. Intriguingly, charge density waves are also pervasive in quantum matters, while their impacts on the effective mass and Fermi velocity of electrons are short of systematic scrutiny. Dr. Ming-Wen Chu and the collaborators in National Taiwan University address this emergent question by advanced momentum-dependent electron energy loss spectroscopy and use the semimetal CuTe as the model quantum material. Surprisingly, the growth in the charge-density-wave order in CuTe at reduced temperatures lightens and speeds up the electrons by 20%, at odds with the established wisdom in classical metals. Thorough inspections underpin the central role played by the charge-density-wave gap opening in the Dirac-like bands that are iconic to quantum matters, CuTe stands out as an essential step for the rich world of quantum-material physics, with the momentum-dependent electron energy loss spectroscopy demonstrated as a useful probe for this type of physics.
Dr. Ming-Wen Chu’s email address: [email protected]
