Wandering principal optical axes in van der Waals triclinic materials Ermolaev Georgy A. Voronin Kirill V. Toksumakov Adilet N. Grudinin Dmitriy V. Fradkin Ilia M. Mazitov Arslan Slavich Aleksandr S. Tatmyshevskiy Mikhail K. Yakubovsky Dmitry I. Solovey Valentin R. Kirtaev Roman V. Novikov Sergey M. Zhukova Elena S. Kruglov Ivan Vyshnevyy Andrey A. Baranov Denis G. Ghazaryan Davit A. Arsenin Aleksey V. Martin-Moreno Luis Volkov Valentyn S. Novoselov Kostya S. 2024 research-article