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TT: Fachverband Tiefe Temperaturen

TT 9: f-Electron Systems and Heavy Fermions II

TT 9.8: Talk

Monday, March 27, 2023, 16:45–17:00, HSZ 201

Orbital-selective Mott transition and heavy-fermion physics in the van der Waals ferromagnet Fe_3−xGeTe₂ — •Frank Lechermann¹, Xiaojian Bai², Yaohua Liu², Yongqiang Cheng², Alexander I. Kolesnikov², Feng Ye², Travis J. Williams², Songxue Chi², Tao Hong², Garrett E. Granroth², Andrew F. May³, and Stuart Calder² — ¹Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44780 Bochum, Germany — ²Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA — ³Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

The van der Waals ferromagnet Fe_3−xGeTe₂ is a fascinating material that attracts combined strong interest from magnetoelectronics as well as from strong correlation physics. While near room temperature, the possibilities to exfoliate conducting ferromagnetic layers is investigated, at temperatures below T∼ 100 K the system displays surprising signatures of heavy-fermion physics. By means of first-principles many-body calculations, we here show that the latter temperature regime is governed by a rare orbital-selective Mott phase. This leads to emergent Kondo(-lattice) behavior in an unique transition-metal 3d compound, accompanied by antiferromagnetic fluctuations within the ferromagnetic phase. These fluctuations are experimentally revealed by neutron scattering.