바니어 함수는 실공간에서 국소화어 있어서 응집물질물리학에서 전자의 상태를 기술하는 다양한 분야에서 널리 사용되는 개념이자 도구이다. 하지만, 기존의 이론은 소수의 에너지 밴드 상태만 기술할 수 있었기 때문에 무한히 많은 밴드를 다루어야 하는 응답 특성의 연구에 이용하기 어려운 한계가 있었다. 우리 학부의 석박통합과정생인 임재모씨(제1저자이자 교신저자)와 박철환 교수(교신저자)는 외부 섭동에 대한 전자 바니어 함수의 섭동 이론을 개발하여 다양한 응답 특성을 계산할 수 있게 만들었다. 기존의 방법론으로 제일원리로부터 정확하고 빠르게 계산할 수 없었던 세 가지 계산을 (온도에 따른 규소의 간접 흡광도, WTe₂의 스핀 이동 전도도와 스핀 홀 전도도) 예로 들어서 새로운 이론의 유용함을 보였다.

Jae-Mo Lihm and Cheol-Hwan Park, “Wannier Function Perturbation Theory: Localized Representation and Interpolation of Wave Function Perturbation,” Phys. Rev. X 11, 041053 (2021).

Link: https://journals.aps.org/prx/abstract/10.1103/PhysRevX.11.041053