Physics
Dept Seminar
October 14, Monday
Materials with Broken
Mirror Symmetries
Prof. Junjie
Yang
Dept
of Physics, NJIT
(Materials
Physics, Host: Tyson)
Time: 11:45 am - 12:45 pm with 11:30 am teatime
Room: ECE 202
Material properties are governed by fundamental
symmetries, such as space inversion, mirror reflection, and time-reversal
symmetries. New material functionalities can only emerge when these symmetries
are broken. For example, breaking space inversion symmetry can induce
ferroelectricity, while breaking time-reversal symmetry can result in
ferromagnetism. Both ferroelectric and ferromagnetic materials have played
crucial roles in modern technologies and industries. Materials with broken
mirror reflection symmetries are relatively less studied, although a broad
family of such materials exists. Breaking mirror symmetry can give rise to
various exotic phenomena, especially when materials are subjected to external
electric or magnetic fields or interact with spin ordering. These phenomena
include electric field-induced chirality, non-reciprocal spin waves, and magnetic
order-induced ferro-rotational order. In this talk, we will discuss emergent
material functionalities in several typical materials with broken mirror
symmetries, such as RbFe(SO₄)₂, Ni₃TeO₆,
and M₁/₃TaS₂.