Origin of diverse nematic orders in Fe-based superconductors: 45∘ rotated nematicity in AFe2As2(A=Cs,Rb)

Seiichiro Onari; Hiroshi Kontani

doi:10.1103/PhysRevB.100.020507

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Origin of diverse nematic orders in Fe-based superconductors: 45∘ rotated nematicity in AFe2As2(A=Cs,Rb)

Seiichiro Onari, Hiroshi Kontani

DOI 10.1103/PhysRevB.100.020507 · Physical Review B

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Abstract

The origin of diverse nematicity and their order parameters in Fe-based superconductors have been attracting increasing attention. Recently, a new type of nematic order has been discovered in heavily hole-doped (nd=5.5) compound AFe2As2(A=Cs,Rb). The discovered nematicity has B2g(=dxy) symmetry, rotated by 45∘ from the B1g(=dx2−y2) nematicity in usual compounds with nd≈6. We predict that the “nematic bond order,” which is the symmetry breaking of the correlated hopping, is responsible for the B2g nematic order in AFe2As2. The Dirac pockets in AFe2As2 is essential to stabilize the B2g bond order. Both B1g and B2g nematicity in A1−xBaxFe2As2 are naturally induced by the Aslamazov-Larkin many-body process, which describes the spin-fluctuation-driven charge instability. The present study gives a great hint to control the nature of charge nematicity by modifying the orbital character and the topology of the Fermi surface.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
RbFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2.5	Pressure not reported	unknown
CsFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.8	Pressure not reported	unknown