 During that time, he invented the qPlus sensor, a new probe for atomic force microscopy and continued experimental and theoretical work on the force microscope at the chair of Professor Jochen Mannhart at University of Augsburg where he received a habilitation in 2001.In 2006, he joined the faculty at the Department of Physics at the University of Regensburg in Germany.From about 2005, he collaborated with the scanning tunneling microscopy groups of IBM Almaden Research Center and IBM Zurich Research Laboratory and from about 2010 with National Institute of Standards and Technology to help to establish combined scanning tunneling microscopy and atomic force microscopy at ultralow temperatures.