2017/01/31 by Sayed Ali Akbar Ghorashi, Seth Davis, Matthew S. Foster · 1 citation
Materials Science · Physics and Astronomy · #Chemical and Physical Properties of Materials #Fermion #Gapless playback #MAJORANA #Majorana fermion #Pairing #Quantum and electron transport phenomena #Superconductivity #Surface (topology) #Surface states #Topological Materials and Phenomena #Topological insulator #Topology (electrical circuits) #cond-mat.dis-nn #cond-mat.mes-hall #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.95.144503
published as Phys. Rev. B 95, 144503 (2017) · 13 pages, 5 figures, published version
openalex created_date 2017/01/26 · arxiv created 2017/04/03 · openalex publication_date 2017/04/03 · arxiv updated 2017/04/12 · openalex updated_date 2026/08/06
We study the Majorana surface states of higher-spin topological superconductors (TSCs) that could be realized in ultracold atomic systems or doped semimetals with spin-orbit coupling. As a paradigmatic example, we consider a model with p-wave pairing of spin-3/2 fermions that generalizes 3He\ensuremath-B. This model has coexisting linear and cubic dispersing Majorana surface bands. We show that these are unstable to interactions, which can generate a spontaneous surface thermal quantum Hall effect (TQHE). By contrast, nonmagnetic quenched disorder induces a surface conformal field theory (CFT) that is stable against weak interactions: topological protection is enhanced by disorder. Gapless surface states of higher-spin TSCs could therefore be robustly realized in solid-state systems, where disorder is inevitable. The surface CFT is characterized by universal signatures that depend only on the bulk topological winding number, and they include power-law scaling of the density of states, a universal multifractal spectrum of local density of states fluctuations, and a quantized ratio of the longitudinal thermal conductivity \ensuremathκxx divided by temperature T. By contrast, \ensuremathκxx/T for the clean surface without TQHE order would diverge as T\ensuremath→0. Since disorder stabilizes the conducting Majorana surface fluid and quantizes thermal transport, our results suggest a close analogy between bulk TSCs and the integer quantum Hall effect.