diff --git a/main.tex b/main.tex index 214c5f1901e97652a7a66a1c8bedec1877e56d93..a3f0ca613e1e35c1c5a3863bb17451b8fa53183a 100644 --- a/main.tex +++ b/main.tex @@ -5,6 +5,7 @@ superscriptaddress, floatfix, longbibliography]{revtex4-2} \usepackage[version=4]{mhchem} \usepackage[dvipsnames]{xcolor} +\usepackage{bbold} \definecolor{first}{RGB}{0,153,230} \definecolor{second}{RGB}{40,37,110} @@ -150,6 +151,13 @@ studies\,\cite{wolf2018,wolf2022a}, we treat the interacting part $H_\mathrm{int}$ with the functional renormalization group (FRG), a short introduction is given below. +Previous FRG studies including Rashba-SOC have been conducted on the +square-lattice Rashba Hubbard model in Ref.~\onlinecite{beyer2023}, on the +triangular lattice with attractive electron electron interactions in +Ref.~\onlinecite{schober2016}. +Studies for SOC of non-Rashba type have been conducted on twisted bilayer +\ce{PtSe2} in Ref.~\onlinecite{klebl2022a}. + \section{Model and Method} \label{sec:modelmethod} @@ -214,7 +222,6 @@ neighbor density-density interaction according to \end{equation} where $\bar \sigma$ is the opposing spin to $\sigma$. - \subsection{Truncated Unity Functional Renormalization Group} In order to properly resolve the different possible particle-particle and particle-hole instabilities of the triangular lattice Rashba-Hubbard model it @@ -224,12 +231,6 @@ we choose the functional renormalization group (FRG) for its wide applicability and advantageous numerical scaling. Furthermore, the results of FRG can trivially exhibit singlet-triplet mixing, which we expect to find in SOC systems. -Previous FRG studies including Rashba-SOC have been conducted on the -square-lattice Rashba Hubbard model in Ref.~\onlinecite{beyer2023}, on the -triangular lattice with attractive electron electron interactions in -Ref.~\onlinecite{schober2016}. -Studies for SOC of non-Rashba type have been conducted on twisted bilayer -\ce{PtSe2} in Ref.~\onlinecite{klebl2022a}. \begin{figure} \centering @@ -273,14 +274,16 @@ Ref.\,\onlinecite{beyer2022a}. \subsection{Analysis of Results} \subsubsection{Particle-particle instabilities} -To accurately determine the nature of particle-particle instabilities we -calculate the truncated unity susceptibility as previously described in +To determine the nature of particle-particle instabilities we calculate the +P-channel truncated unity susceptibility as previously described in Ref.~\cite{beyer2022a,klebl2022a}. The obtained eigenstate we decompose into singlet-like ($\Psi$) and triplet-like ($d_x, d_y, d_z$) components, calculating the magnitude the -respective subspaces. -\todo{I think the d basis should be defined explicitly here, -heavily used after this point.} +respective subspaces according to +\begin{equation} + v = [\Psi(\bvec k) \mathbb{1} + \bvec d(\bvec k) + \cdot \hat{\bvec{\sigma}}] i \hat \sigma_y \, . +\end{equation} Notably, at finite Rashba-SOC the eigenstate is expected to have finite weight in both subspaces, due to the singlet-triplet mixing. @@ -610,21 +613,28 @@ effect of the Rashba SOC. \section{Irreducible representation basis functions in the spin representation} \label{app:spin-irreps} -To get the irreducible representations of the two spins, we begin by constructing -the symmetry group representation of for a single spin, which we denote as $S(C_{6v})$. -The representation of the whole group can be constructed from the two generators, -which are one of the $C_6$ rotations: +To get the irreducible representations of the two spins, we begin by +constructing the symmetry group representation of for a single spin, which we +denote as $S(C_{6v})$. The representation of the whole group can be +constructed from the two generators, which are one of the $C_6$ rotations: \begin{equation} - S(C_6) = \exp \bigg( \frac{-i \pi \hat{\tau}_z}{6} \bigg) = + S(C_6) = \exp \bigg( \frac{-i \pi \hat{\sigma}_z}{6} \bigg) + = \begin{pmatrix} \sqrt{3} - i & 0 \\ - 0 & \sqrt{3} + i + 0 & \sqrt{3} + i \end{pmatrix} , \end{equation} -where $\tau_z$ is the third Pauli matrix, as well as a reflection $\sigma_1$, -which we will take to be the reflection in the $y$-axis: +where $\hat\sigma_z$ is the third Pauli matrix, as well as a reflection $m_y$, +which we will take to be the mirror w.r.t. the $y$-axis: \begin{equation} - S(\sigma_1) = i \hat{\tau}_x \, . + S(m_y) = i \hat{\sigma}_x + = + \begin{pmatrix} + 0 & i \\ + i & 0 + \end{pmatrix} + \, . \end{equation} Given the symmetry group representation acting on a single spin $S(C_{6v})$, the