Volume 121, Number 2, January 2018
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||16 March 2018|
Strain-induced recovery of electronic anisotropy in 90°-twisted bilayer phosphorene
1 Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University - Lanzhou 730000, China
2 First Hospital of Lanzhou University - Lanzhou 730000, China
3 Key Laboratory of Special Function Materials and Structure Design of the Ministry of Education, Lanzhou University - Lanzhou 730000, China
Received: 17 December 2017
Accepted: 26 February 2018
It is well known that anisotropy determines the preferred transport direction of carriers. To manipulate the anisotropy is an exciting topic in two-dimensional materials, where the carriers are confined within individual layers. In this work, it is found that uniaxial strain can tune the electronic anisotropy of the 90°-twisted bilayer phosphorene. In this unique bilayer structure, the zigzag direction of one layer corresponds to the armchair one of the other layer and vice versa. Owing to this complementary structure, the directional (zigzag or armchair) deformation response to strain of one layer is opposite to that of the other layer, where the in-plane positive Poisson's ratio plays a key role. As a result, the doubly degenerate highest valence bands split, followed by a recovery of anisotropy. More interestingly, such an anisotropy, namely, the ratio of the effective mass along the direction to that along the direction, reaches as high as 6 under a small strain of 1%, and keeps nearly unchanged up to a strain of 3%. In addition, high anisotropy only holds for hole carriers as the conduction band is insensitive to strain. These findings should shed new light on the design of semiconducting devices, where the hole acts as the transport carrier.
PACS: 73.22.-f – Electronic structure of nanoscale materials and related systems / 68.65.-k – Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
© EPLA, 2018
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