Determination of exchange energy (IMAGE) Swiss Nanoscience Institute, University of Basel Caption The two-dimensional semiconductor material molybdenum disulfide is filled with electrons (red spheres). The electron-electron interaction causes the spins of all electrons (red arrows) to align in the same direction. The exchange energy required to flip a single electron spin in the ferromagnetic state can be determined by the separation between two specific spectral lines. Credit N. Leisgang, Harvard University, formerly Department of Physics, University of Basel/Scixel Usage Restrictions Only to be used mentioning the credits License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.