Magnetic Stress-Driven Metal-Insulator Transition in Strongly Correlated Antiferromagnetic CrN
Bidesh Biswas, Sourav Rudra, Rahul Singh Rawat, Nidhi Pandey, Shashidhara Acharya, A. S. Joseph, Ashalatha Indiradevi Kamalasanan Pillai, Manisha Bansal, Muireann de h-Óra, Debendra Prasad Panda, Arka Bikash Dey, Florian Bertram, Chandrabhas Narayana, Judith L. MacManus‐Driscoll, Tuhin Maity, Magnus Garbrecht, Bivas Saha
Abstract
Traditionally, the Coulomb repulsion or Peierls instability causes the metal-insulator phase transitions in strongly correlated quantum materials. In comparison, magnetic stress is predicted to drive the metal-insulator transition in materials exhibiting strong spin-lattice coupling. However, this mechanism lacks experimental validation and an in-depth understanding. Here we demonstrate the existence of the magnetic stress-driven metal-insulator transition in an archetypal material, chromium nitride. Structural, magnetic, electronic transport characterization, and first-principles modeling analysis show that the phase transition temperature in CrN is directly proportional to the strain-controlled anisotropic magnetic stress. The compressive strain increases the magnetic stress, leading to the much-coveted room-temperature transition. In contrast, tensile strain and the inclusion of nonmagnetic cations weaken the magnetic stress and reduce the transition temperature. This discovery of a new physical origin of metal-insulator phase transition that unifies spin, charge, and lattice degrees of freedom in correlated materials marks a new paradigm and could lead to novel device functionalities.