Bright and Dark Exciton Coherent Coupling and Hybridization Enabled by External Magnetic Fields

被引：5

作者：

Mapara, Varun ^{[1
]}

Barua, Arup ^{[1
]}

Turkowski, Volodymyr ^{[2
]}

Trinh, M. Tuan ^{[1
]}

Stevens, Christopher ^{[1
]}

Liu, Hengzhou ^{[1
]}

Nugera, Florence A. ^{[1
]}

Kapuruge, Nalaka ^{[1
]}

Gutierrez, Humberto Rodriguez ^{[1
]}

Liu, Fang ^{[3
]}

Zhu, Xiaoyang ^{[4
]}

Semenov, Dmitry ^{[5
]}

McGill, Stephen A. ^{[5
]}

Pradhan, Nihar ^{[6
]}

Hilton, David J. ^{[7
]}

Karaiskaj, Denis ^{[1
]}

机构：

[1] Univ S Florida, Dept Phys, Tampa, FL 33620 USA

[2] Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA

[3] Stanford Univ, Dept Chem, Stanford, CA 94305 USA

[4] Columbia Univ, Dept Chem, New York, NY 10027 USA

[5] Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA

[6] Jackson State Univ, Dept Chem Phys & Atmospher Sci, Layered Mat & Device Phys Lab, Jackson, MS 39217 USA

[7] Univ Alabama Birmingham, Dept Phys, Birmingham, AL 35294 USA

来源：

NANO LETTERS | 2022年 / 22卷 / 04期

基金：

美国国家科学基金会; 美国能源部;

关键词：

Nonlinear optical spectroscopy; Four-wave mixing spectroscopy; Two-dimensional excitons; Transition metal dichalcogenides; Time-dependent DFT; VALLEY POLARIZATION; QUANTUM BEATS; MOS2; MONOLAYERS; DYNAMICS;

D O I：

10.1021/acs.nanolett.1c04667

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Magnetic field- and polarization-dependent measurements on bright and dark excitons in monolayer WSe2 combined with time-dependent density functional theory calculations reveal intriguing phenomena. Magnetic fields up to 25 T parallel to the WSe2 plane lead to a partial brightening of the energetically lower lying exciton, leading to an increase of the dephasing time. Using a broadband femtosecond pulse excitation, the bright and partially allowed excitonic state can be excited simultaneously, resulting in coherent quantum beating between these states. The magnetic fields perpendicular to the WSe2 plane energetically shift the bright and dark excitons relative to each other, resulting in the hybridization of the states at the K and K' valleys. Our experimental results are well captured by time-dependent density functional theory calculations. These observations show that magnetic fields can be used to control the coherent dephasing and coupling of the optical excitations in atomically thin semiconductors.

引用

页码：1680 / 1687

页数：8