Unusual Dirac fermions on the surface of noncentrosymmetric $\alpha$ - BiPd superconductor

Abstract

Combining multiple emergent correlated properties such as superconductivity and magnetism within the topological matrix can have exceptional consequences in garnering new and exotic physics. Here, we study the topological surface states from a noncentrosymmetric $\alpha$-BiPd superconductor by employing angle-resolved photoemission spectroscopy (ARPES) and first principle calculations. We observe that the Dirac surface states of this system have several interesting and unusual properties, compared to other topological surface states. The surface state is strongly anisotropic and the in-plane Fermi velocity varies rigorously on rotating the crystal about the $y$-axis. Moreover, it acquires an unusual band gap as a function of $k_y$, possibly due to hybridization with bulk bands, detected upon varying the excitation energy. Coexistence of all the functional properties, in addition to the unusual surface state characteristics make this an interesting material.

submitted on 26th April, 2016; to appear in PRL

References in corpus (5)

• Topological Insulators with Inversion Symmetry
• Topological Phases of Noncentrosymmetric Superconductors: Edge States, Majorana Fermions, and the Non-Abelian Statistics
• Dirac Surface States and Nature of Superconductivity in Noncentrosymmetric BiPd
• Prediction of weak topological insulators in layered semiconductors
• Observation of Andreev bound state and multiple energy gaps in the non-centrosymmetric superconductor BiPd

Cited by in corpus (6)

• Observation of Dirac surface states in the hexagonal PtBi2, a possible origin of the linear magnetoresistance
• Strong-Coupling Superconductivity with $T_c$ $\sim$ 10.8 K Induced by P Doping in the Topological Semimetal Mo${}_5$Si${}_3$
• Exceptional Dirac states in a non-centrosymmetric superconductor, BiPd
• Fermi surface and band structure of BiPd from ARPES studies
• Temperature dependence of the lower critical field of the noncentrosymmetric superconductor $\alpha$-BiPd
• Ab initio study of orbital-selective superconductivity in $\gamma$-BiPd