Table 1 Calculated partial Berry phases and corresponding polarizations for the non-polar CS R\(\bar{3}\)c and polar NCS R3c hexagonal supercells of LiOsO\(_3\), using the PBE-GGA with mBp and mWf schemes.

From: Nonzero spontaneous electric polarization in metals: novel predictive methods and applications

 

mBp

mWf

NCS R3c

CS R\(\bar{3}\)c

NCS R3c

CS R\(\bar{3}\)c

\(\varphi _{\textit{ion}}\)

2.7396

6.2832

\(\varphi _{\textit{el}}^{{\text { (II)}}}\)

− 2.2402

0.0000

\(\phi _{\textit{el}}^{(\text {I}^*)}\)

0.3267

− 1.5403

\(\phi _{\textit{el}}=\varphi _{\textit{el}}^{{\text { (II)}}} +\phi _{\textit{el}}^{(\text {I}^*)}\)

− 1.9135

− 1.5403

\(\phi =\varphi _{\textit{ion}}+2\phi _{\textit{el}}\)

− 1.0784

3.2026

\(\textbf{P}_{\textit{ion}}\)

0.3130

0.0000

0.3130

0.0000

\(\textbf{P}_{\textit{el}}^{\text {(II)}}\)

0.2060

0.0000

0.2076

0.0000

\(\textbf{P}_{\textit{el}}^{(\text {I}^*)}\)

0.0746

− 0.3519

0.0706

− 0.3584

\(\textbf{P}_{\textit{el}}=\textbf{P}_{\textit{el}}^{\text {(II)}} +\textbf{P}_{\textit{el}}^{(\text {I}^*)}\)

0.2806

− 0.3519

0.2782

− 0.3584

\(\textbf{P}=\textbf{P}_{\textit{ion}}+\textbf{P}_{\textit{el}}\)

0.5936

− 0.3519

0.5912

− 0.3584

\(\Delta {\textbf{P}}=\textbf{P}\text {(R3c)}-\textbf{P}(\text {R}\bar{3}\text {c})\)

0.9455

0.9496

  1. The values for the electronic parts of the Berry phases (\(\phi _{\textit{el}}\)) and polarizations (\(\textbf{P}_{\textit{el}}\)) were obtained by adding the contributions from class II (\(\varphi _{\textit{el}}^{{\text { (II)}}}\) and \(\textbf{P}_{\textit{el}}^{\text {(II)}}\)) and class I\(^*\) (\(\phi _{\textit{el}}^{(\text {I}^*)}\) and \(\textbf{P}_{\textit{el}}^{(\text {I}^*)}\)). Similarly, total Berry phases (\(\phi\)) and polarizations (\(\textbf{P}\)) were calculated by adding ionic and electronic contributions. Spontaneous polarizations (\(\Delta {\textbf{P}}\)) were derived by subtracting the polarizations of R3c and R\(\bar{3}\)c structures as \(\Delta {\textbf{P}}=\textbf{P}\text {(R3c)}-\textbf{P}(\text {R}\bar{3}\text {c})\). The results are given modulo \(e\textbf{R}/\Omega\) and will be unwrapped in “Uniquifying of spontaneous polarization of LiOsO\(_{{3}}\) by finding the best branch” following the procedure proposed by Resta and Vanderbilt in Ref.57. Refer to Sect. 3 of the SMs for more detailed information.