8 papers · 1 filter
Direct probing the quantum geometric tensor for bosonic collective excitations
Chi Wu, Takashi Oka, Shuichi Murakami +1
The quantum geometric tensor (QGT), whose real and imaginary parts define the quantum metric and Berry curvature, encodes the intrinsic geometry of quantum states. While electronic…
Local expression of fractional corner charges in obstructed atomic insulators and relationship with the fractional disclination charges
Hidetoshi Wada, Shuichi Murakami
In obstructed atomic insulators, fractionally quantized charges appear at the corners of the crystals in the shapes of vertex-transitive polyhedra, and are given by the filling ano…
Topological charge and bulk-surface correspondence for quad-helicoid surface states in topological semimetals with two glide-time-reversal symmetries
Taiki Yukitake, Shuichi Murakami
Quad-helicoid surface states (QHSSs) are unique surface states with two pairs of helicoid surface states in topological semimetals such as Dirac semimetals. So far, topologically p…
Advances in Phonons: From Band Topology to Phonon Chirality
Tiantian Zhang, Yizhou Liu, Hu Miao +1
Phonons, the quantized collective vibrations of a crystal lattice, are among the most fundamental bosonic excitations in condensed matter systems. They govern thermal transport, me…
Unraveling a chemical-bond-driven root of topology in three-dimensional chiral crystals
Shungo Aoyagi, Shunsuke Kitou, Yuiga Nakamura +6
Chirality manifests across multiple scales, yielding unique phenomena that break mirror symmetry. In chiral materials, unexpectedly large spin-filtering or photogalvanic effects ha…
Theory of fractional corner charges in cylindrical crystal shapes
Hidetoshi Wada, Tiantian Zhang, Shuichi Murakami
Recent studies showed that topologically trivial insulators may have fractionally quantized corner charges due to the topological invariant called a filling anomaly. Such crystal s…