Comparison between our abundance differences and those reported in the literature for planet-host binaries also analysed differentially. Systems with only one or the two components known to host planets are shown with blue and red symbols, respectively. For systems with only one planet host, the convention is star without planet minus star with planet. Source of the data: HAT-P-1 (Liu et al. 2014), HAT-P-4 (Saffe et al. 2017), 16 Cyg (Tucci Maia et al. 2014), HD 80606/HD 80607 (Liu et al. 2018), WASP-94 (Teske et al. 2016a), XO-2 (Ramírez et al. 2015), HD 133131 (Teske et al. 2016b), and HD 20781/HD 20782 (Mack et al. 2014). For elements with abundances corresponding to two ionisation stages, we followed the procedure outlined in Sect. 5.2. For WASP-94, we considered the dataset with strong lines excluded (see Teske et al. 2016a).