RT Journal Article
SR Electronic
T1 Filling-enforced quantum band insulators in spin-orbit coupled crystals
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1501782
DO 10.1126/sciadv.1501782
VO 2
IS 4
A1 Po, Hoi Chun
A1 Watanabe, Haruki
A1 Zaletel, Michael P.
A1 Vishwanath, Ashvin
YR 2016
UL http://advances.sciencemag.org/content/2/4/e1501782.abstract
AB An early triumph of quantum mechanics was the explanation of metallic and insulating behavior based on the filling of electronic bands. A complementary, classical picture of insulators depicts electrons as occupying localized and symmetric Wannier orbitals that resemble atomic orbitals. We report the theoretical discovery of band insulators for which electron filling forbids such an atomic description. We refer to them as filling-enforced quantum band insulators (feQBIs) because their wave functions are associated with an essential degree of quantum entanglement. Like topological insulators, which also do not admit an atomic description, feQBIs need spin-orbit coupling for their realization. However, they do not necessarily support gapless surface states. Instead, the band topology is reflected in the insulating behavior at an unconventional filling. We present tight binding models of feQBIs and show that they only occur in certain nonsymmorphic, body-centered cubic crystals.