Fermi Rubik’s Cube in High-Pressure Induced Chlorine-Rich Compounds

Abstract In the quasi-free electron model, the Fermi surface spreads into a sphere in the Brillouin zone, i.e., the Fermi sphere. The Fermi sphere exists widely in metal systems, no matter whether the crystal is in a body-center cubic, face-center cubic, or hexagonal close-packed lattice. Here, we report a class of compounds stabilized at high pressure with Rubik’s cubic Fermi surface, in which the representative example is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>P</mml:mi> <mml:mi>m</mml:mi> <mml:mover accent="true"> <mml:mn>3</mml:mn> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>n</mml:mi> </mml:mrow> </mml:math> -CaCl 3 . Our quantum-mechanical variable-composition evolutionary simulations predict the thermal stabilities of CaCl 3 , and the tight-binding model reveals that its unique Fermi surface originates from the quasi-one-dimensional interaction, structural symmetric protection, and particle-hole symmetry breaking. Furthermore, by its flat and steep band structure, CaCl 3 has a huge span of effective mass from 9.08 × 10 3 m e (super-heavy) to 5.13 × 10 −4 m e on the Fermi level, which supplies an interesting platform for quasiparticle research.