Executive Summary : | Topological superconductors are a unique class of superconductors that have non-trivial bulk topology, leading to protected zero-energy surface Majorana modes. These Majorana modes can be used in fault-tolerant quantum computers with topologically protected qubits. However, bulk topological superconducting materials are rare and often have weak topological protection, leading to unstable Majorana modes. This proposal aims to overcome this issue by theoretically investigating real symmetry-protected topological metals to find intrinsic robust topological superconductivity. Topological metals are special metallic materials with protected band-crossings near the Fermi energy. They are of two types: Z2 topological metals with a continuous direct band-gap and band-crossings protected by a Z2 topological invariant, and gapless nodal topological semimetals with different dimensionality of the band-crossings. The low-energy excitations near a point node can be Dirac or Weyl fermions or multi-fold fermions protected by nonsymmorphic symmetries. The project aims to investigate the fate of unconventional superconducting instabilities that break the symmetries protecting the normal state topology of a topological metal, as well as the consequences of the associated topological phase transition. The project will also establish a detailed phase diagram arising from the interplay among strong-correlation-driven topology, superconductivity, and quantum fluctuations in topological metals. |