Measuring and Tuning the Potential Landscape of Electrostatically Defined Quantum Dots in Graphene

被引：13

作者：

Behn, Wyatt A. ^{[1
]}

Krebs, Zachary J. ^{[1
]}

Smith, Keenan J. ^{[1
]}

Watanabe, Kenji ^{[2
]}

Taniguchi, Takashi ^{[3
]}

Brar, Victor W. ^{[1
]}

机构：

[1] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA

[2] Natl Inst Mat Sci, Res Ctr Funct Mat, Tsukuba, Ibaraki 3050044, Japan

[3] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, Tsukuba, Ibaraki 3050044, Japan

来源：

NANO LETTERS | 2021年 / 21卷 / 12期

基金：

美国国家科学基金会;

关键词：

2D materials; quantum dots; surface potentials; Kelvin probe force microscopy; scanning tunneling spectroscopy; graphene; MAGIC-ANGLE; FORCE MICROSCOPY; DIRAC FERMIONS; SPECTROSCOPY; RESOLUTION; CONTACT;

D O I：

10.1021/acs.nanolett.1c00791

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

We use Kelvin probe force microscopy (KPFM) to probe the carrier-dependent potential of an electrostatically defined quantum dot (QD) in a graphene/hexagonal boron nitride (hBN) heterostructure. We show that gate-dependent measurements enable a calibration scheme that corrects for uncertainty inherent in typical KPFM measurements and accurately reconstructs the potential well profile. Our measurements reveal how the well changes with carrier concentration, which we associate with the nonlinear dependence of graphene's work function on carrier density. These changes shift the energy levels of quasi-bound states in the QD which we can measure via scanning tunneling spectroscopy (STS). We show that the experimentally extracted energy levels closely compare with wave functions calculated from the reconstructed KPFM data. This methodology, where KPFM and STS data are simultaneously acquired from 2D materials, allows the quasiparticle response to an electrostatic potential to be determined in a self-consistent way.

引用

页码：5013 / 5020

页数：8

共 61 条

[11] Multichannel scanning probe microscopy and spectroscopy of graphene moire structures [J].