Metanematic transitions in a bilayer system: Application to the bilayer ruthenate

Abstract

It was suggested that the two consecutive metamagnetic transitions and the large residual resistivity discovered in Sr 3 Ru 2 O 7 can be understood via the nematic order and its domains in a single layer system. However, a recently reported anisotropy between two longitudinal resistivities induced by tilting the magnetic field away from the c axis cannot be explained within the single layer nematic picture. To fill the gap in our understanding within the nematic order scenario, we investigate the effects of bilayer coupling and in-plane magnetic field on the electronic nematic phases in a bilayer system. We propose that the in-plane magnetic field in the bilayer system modifies the energetics of domain formation, since it breaks the degeneracy of two different nematic orientations. Thus, the system reveals a pure nematic phase with a resistivity anisotropy in the presence of an in-plane magnetic field. In addition to the nematic phase, the bilayer coupling opens a different route to a hidden nematic phase that preserves the x-y symmetry of the Fermi surfaces.

Electric Octupole Order in Bilayer Ruthenate Sr3Ru2O7

“…Thus, the elaborate model adopted in this paper is necessary for the description of the EO state. Although the antiferro stacking of the d-wave nematic order has been studied, 27,28 some essential factors have been neglected. Figure 4 shows the pronounced spin splitting in the 3 rd and 4 th bands.…”

“…On the other hand, we can consider the two multipole states distinguished by the symmetry when we take into account the bilayer structure in the unit cell. 27,28 One is the ferro stacking of quadrupoles in the bilayer, and the other is the antiferro stacking. When we regard the unit cell as a multimer, the former is classified into the EQ order, and the latter is the EO order that we focus on.…”

Fermi surface instabilities at finite temperature

“…In particular, broken symmetry phases arise due to electron-electron interactions, within the Landau-Fermi liquid description [4][5][6][7][8][9][10][11] . In some cases, such instabilities lead to nematic phases [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] . A comprehensive review about nematic Fermi fluids with an extensive list of references could be found in Ref.…”

Transport signatures of electronic-nematic stripe phases

“…It is striking that for the parallel modulated nematic state only ρ yy e becomes larger than ρ 0 , whereas ρ xx e remains largely unchanged from the isotropic value. This is in contrast to the pure nematic phase, where the conductivity along one lattice direction is smaller than along the other lattice direction, while the average of both is close to the isotropic conductivity, [11,12,34] resulting in one principal resistivity component smaller and the other larger than the isotropic resistivity ρ 0 .…”