Abstract

We report the first experimental demonstration that the Chern numbers of the moiré frontier bands undergo sign reversal at a critical twist angle ~1.42° in twisted WSe₂ bilayers. Using scanning tunnelling microscopy and spectroscopy, we directly measure layer-pseudospin skyrmion textures of twisted WSe₂ and show twist-angle-dependent layer-pseudospin polarization near the critical twist angle, revealing the origin of the observed Chern number sign reversal.

Abstract

We report the first experimental demonstration that the Chern numbers of the moiré frontier bands undergo sign reversal at a critical twist angle ~1.42° in twisted WSe₂ bilayers. Using scanning tunnelling microscopy and spectroscopy, we directly measure layer-pseudospin skyrmion textures of twisted WSe₂ and show twist-angle-dependent layer-pseudospin polarization near the critical twist angle, revealing the origin of the observed Chern number sign reversal.

Abstract

We report the first experimental demonstration that the Chern numbers of the moiré frontier bands undergo sign reversal at a critical twist angle ~1.42° in twisted WSe₂ bilayers. Using scanning tunnelling microscopy and spectroscopy, we directly measure layer-pseudospin skyrmion textures of twisted WSe₂ and show twist-angle-dependent layer-pseudospin polarization near the critical twist angle, revealing the origin of the observed Chern number sign reversal.

Abstract

We report the first experimental demonstration that the Chern numbers of the moiré frontier bands undergo sign reversal at a critical twist angle ~1.42° in twisted WSe₂ bilayers. Using scanning tunnelling microscopy and spectroscopy, we directly measure layer-pseudospin skyrmion textures of twisted WSe₂ and show twist-angle-dependent layer-pseudospin polarization near the critical twist angle, revealing the origin of the observed Chern number sign reversal.