yii2 remember me default checked, how can uncheck

When i login in yii2 and unchecked remember me but i always get remember me as checked in login form. how can we unchecked by default. Here is the controller code

public function login() {
        if ($this->validate()) {
            return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600 * 24 * 30 : 0);
        } else {
            return false;
        }
}

$this->rememberMe always get yes.